Use newer ruff style - #2031

This resolves two warnings about Ruff configuration, by:

- No longer setting `ignore-init-module-imports = true` explicitly,
  which was deprecated since `ruff` 0.4.4. We primarily use `ruff`
  via `pre-commit`, for which this deprecation has applied since we
  upgraded the version in `.pre-commit-config.yaml` from 0.4.3 to
  0.6.0 in d1582d1 (gitpython-developers#1953).

  We continue to list `F401` ("Module imported but unused") as not
  automatically fixable, to avoid inadvertently removing imports
  that may be needed.

  See also:
  https://docs.astral.sh/ruff/settings/#lint_ignore-init-module-imports

- Rename the rule `TCH004` to `TC004`, since `TCH004` is the old
  name that may eventually be removed and that is deprecated since
  0.8.0. We upgraded `ruff` in `.pre-commit-config.yml` again in
  b7ce712 (gitpython-developers#2031), from 0.6.0 to 0.11.12, at which point this
  deprecation applied.

  See also https://astral.sh/blog/ruff-v0.8.0.

These changes make those configuration-related warnings go away,
and no new diagnostics (errors/warnings) are produced when running
`ruff check` or `pre-commit --all-files`. No F401-related
diagnostics are triggered when testing with explicit
`ignore-init-module-imports = false`, in preview mode or otherwise.

This commit also adds the version lower bound `>=0.8` for `ruff` in
`requirements-dev.txt`. (That file is rarely used, as noted in
a8a73ff (gitpython-developers#1871), but as long as we have it, there may be a benefit
to excluding dependency versions for which our configuration is no
longer compatible.)

This resolves two warnings about Ruff configuration, by:

- No longer setting `ignore-init-module-imports = true` explicitly,
  which was deprecated since `ruff` 0.4.4. We primarily use `ruff`
  via `pre-commit`, for which this deprecation has applied since we
  upgraded the version in `.pre-commit-config.yaml` from 0.4.3 to
  0.6.0 in d1582d1 (gitpython-developers#1953).

  We continue to list `F401` ("Module imported but unused") as not
  automatically fixable, to avoid inadvertently removing imports
  that may be needed.

  See also:
  https://docs.astral.sh/ruff/settings/#lint_ignore-init-module-imports

- Rename the rule `TCH004` to `TC004`, since `TCH004` is the old
  name that may eventually be removed and that is deprecated since
  0.8.0. We upgraded `ruff` in `.pre-commit-config.yml` again in
  b7ce712 (gitpython-developers#2031), from 0.6.0 to 0.11.12, at which point this
  deprecation applied.

  See also https://astral.sh/blog/ruff-v0.8.0.

These changes make those configuration-related warnings go away,
and no new diagnostics (errors/warnings) are produced when running
`ruff check` or `pre-commit run --all-files`. No F401-related
diagnostics are triggered when testing with explicit
`ignore-init-module-imports = false`, in preview mode or otherwise.

In addition, this commit makes two changes that are not needed to
resolve warnings:

- Stop excluding `E203` ("Whitespace before ':'"). That diagnostic
  is no longer failing with the current code here in the current
  version of `ruff`, and code changes that would cause it to fail
  would likely be accidentally mis-st

- Add the version lower bound `>=0.8` for `ruff` in
  `requirements-dev.txt`. That file is rarely used, as noted in
  a8a73ff (gitpython-developers#1871), but as long as we have it, there may be a
  benefit to excluding dependency versions for which our
  configuration is no longer compatible. This is the only change in
  this commit outside of `pyproject.toml`.

The tox `misc` environment runs `pre-commit run --all-files` with
`SKIP = ruff-format,ruff`, so that it covers the other hooks and
leaves Ruff to the separate `ruff` and `format` environments. Later,
b7ce712 (gitpython-developers#2031) switched the Ruff linting hook in
`.pre-commit-config.yaml` from its id `ruff`, which `ruff-pre-commit`
now keeps only as a legacy alias, to `ruff-check`, but the `SKIP` list
was not updated. pre-commit ignores unknown hook ids in `SKIP`, so
`tox -e misc` has been running `ruff check` again, duplicating the
`ruff` environment:

    ruff check...........................................Passed
    ruff format..........................................Skipped

Skip `ruff-check` instead of `ruff`. Run locally with tox 4.67.1,
`tox -e misc` now reports both Ruff hooks as `Skipped`, and all the
other hooks (`shellcheck`, the `pre-commit-hooks` checks, and
`validate-pyproject`) still run and pass.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

The tox `misc` environment runs `pre-commit run --all-files` with
`SKIP = ruff-format,ruff`, so that it covers the other hooks and
leaves Ruff to the separate `ruff` and `format` environments. Later,
b7ce712 (gitpython-developers#2031) switched the Ruff linting hook in
`.pre-commit-config.yaml` from its id `ruff`, which `ruff-pre-commit`
now keeps only as a legacy alias, to `ruff-check`, but the `SKIP` list
was not updated. pre-commit ignores unknown hook ids in `SKIP`, so
`tox -e misc` has been running `ruff check` again, duplicating the
`ruff` environment:

    ruff check...........................................Passed
    ruff format..........................................Skipped

Skip `ruff-check` instead of `ruff`. Run locally with tox 4.67.1,
`tox -e misc` now reports both Ruff hooks as `Skipped`, and all the
other hooks (`shellcheck`, the `pre-commit-hooks` checks, and
`validate-pyproject`) still run and pass.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

The main CI does not use tox, so the tox configuration can break
without anyone noticing. It has: `tox -e html` stopped working when
9e54de4 (gitpython-developers#2243) removed the `doc` extra, `tox -e misc` has run
`ruff check` again since b7ce712 (gitpython-developers#2031) changed that hook's id, and
the `base_python` fallbacks have not meant what they said since
62c024e (gitpython-developers#1693). New releases of tox and virtualenv can also change
how the configuration behaves, as when tox 4.56.0 made missing
interpreters fail. But running every tox environment is too slow for
every push and pull request.

Add a `tox` workflow that runs on a weekly schedule and through
`workflow_dispatch`. Each job runs the tox environments for one Python
version, from 3.8 to 3.15, on Ubuntu. 3.8 and 3.9 run on
`ubuntu-24.04`, since `setup-python` has no builds of them for Ubuntu
26.04. The 3.12 job also runs `gix`, and the 3.13 job also runs
`ruff`, `format`, `mypy`, `html`, and `misc`. The steps that prepare
for the tests (Rust for GixPython source builds, current Git from the
git-core PPA, `init-tests-after-clone.sh`, and the test Git identity
and aliases) are the same as in `pythonpackage.yml`.

tox and the plugin used below both need Python 3.11 or later, so
`setup-python` also installs Python 3.13, and tox runs on that. tox is
installed unpinned, so that the workflow tests the configuration with
the tox and virtualenv that a contributor would get. The job has only
`contents: read` and uses no secrets.

For running tox on GitHub Actions, there are two tox plugins and one
action:

- `tox-gh`, from the `tox-dev` organization that maintains tox, selects
  the environments for the job's Python version from a mapping in the
  tox configuration, puts each environment's output in its own log
  group, and summarizes the results.
- `tox-gh-actions`, an older plugin maintained outside `tox-dev`, does
  the same with more ways to select environments, and also supports
  tox 3. This project needs only selection by Python version.
- `fedora-python/tox-github-action` runs tox in a Fedora container
  that has most Python versions, but no longer 3.8. It also pulls its
  image by a mutable tag, its repository has no license, and it runs
  tox as root in the container, which would change what GitPython's
  tests see about file ownership and `safe.directory`.

Use `tox-gh`. Selecting environments by version is simple here, but
the log groups make long weekly logs easier to read, and it adds
little risk, since it comes from the `tox-dev` organization, like tox
itself. Its
mapping goes in `[tool.tox.gh.python]` in `pyproject.toml`. tox-gh
does nothing outside GitHub Actions, and without it, `tox config`
only adds a note that `gh` is unused. The job sets
`TOX_GH_MAJOR_MINOR` to the matrix version, as tox-gh documents for
when tox runs on a different Python.

`actionlint`, `zizmor` 1.31.1 (pedantic, with online audits), and
`pinact run --check --verify-comment` report nothing for the new
workflow, and all pre-commit hooks pass. With `GITHUB_ACTIONS=true`
set locally, tox with tox-gh ran only `py38` for
`TOX_GH_MAJOR_MINOR=3.8`, in its own log group, and set up `py313`,
`ruff`, `format`, `mypy`, `html`, and `misc` for 3.13. The workflow
itself has not run on GitHub yet, because `workflow_dispatch` and
`schedule` only work once it is on the default branch.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

The tox `misc` environment runs `pre-commit run --all-files` with
`SKIP = ruff-format,ruff`, so that it covers the other hooks and
leaves Ruff to the separate `ruff` and `format` environments. Later,
b7ce712 (gitpython-developers#2031) switched the Ruff linting hook in
`.pre-commit-config.yaml` from its id `ruff`, which `ruff-pre-commit`
now keeps only as a legacy alias, to `ruff-check`, but the `SKIP` list
was not updated. pre-commit ignores unknown hook ids in `SKIP`, so
`tox -e misc` has been running `ruff check` again, duplicating the
`ruff` environment:

    ruff check...........................................Passed
    ruff format..........................................Skipped

Skip `ruff-check` instead of `ruff`. Run locally with tox 4.67.1,
`tox -e misc` now reports both Ruff hooks as `Skipped`, and all the
other hooks (`shellcheck`, the `pre-commit-hooks` checks, and
`validate-pyproject`) still run and pass.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

The main CI does not use tox, so the tox configuration can break
without anyone noticing. It has: `tox -e html` stopped working when
9e54de4 (gitpython-developers#2243) removed the `doc` extra, `tox -e misc` has run
`ruff check` again since b7ce712 (gitpython-developers#2031) changed that hook's id, and
the `base_python` fallbacks have not meant what they said since
62c024e (gitpython-developers#1693). New releases of tox and virtualenv can also change
how the configuration behaves, as when tox 4.56.0 made missing
interpreters fail. But running every tox environment is too slow for
every push and pull request.

Add a `tox` workflow that runs on a weekly schedule and through
`workflow_dispatch`. Each job runs the tox environments for one Python
version, from 3.8 to 3.15, on Ubuntu. 3.8 and 3.9 run on
`ubuntu-24.04`, since `setup-python` has no builds of them for Ubuntu
26.04. The 3.12 job also runs `gix`, and the 3.13 job also runs
`ruff`, `format`, `mypy`, `html`, and `misc`. The steps that prepare
for the tests (Rust for GixPython source builds, current Git from the
git-core PPA, `init-tests-after-clone.sh`, and the test Git identity
and aliases) are the same as in `pythonpackage.yml`.

tox and the plugin used below both need Python 3.11 or later, so
`setup-python` also installs Python 3.13, and tox runs on that. tox is
installed unpinned, so that the workflow tests the configuration with
the tox and virtualenv that a contributor would get. The job has only
`contents: read` and uses no secrets.

For running tox on GitHub Actions, there are two tox plugins and one
action:

- `tox-gh`, from the `tox-dev` organization that maintains tox, selects
  the environments for the job's Python version from a mapping in the
  tox configuration, puts each environment's output in its own log
  group, and summarizes the results.
- `tox-gh-actions`, an older plugin maintained outside `tox-dev`, does
  the same with more ways to select environments, and also supports
  tox 3. This project needs only selection by Python version.
- `fedora-python/tox-github-action` runs tox in a Fedora container
  that has most Python versions, but no longer 3.8. It also pulls its
  image by a mutable tag, its repository has no license, and it runs
  tox as root in the container, which would change what GitPython's
  tests see about file ownership and `safe.directory`.

Use `tox-gh`. Selecting environments by version is simple here, but
the log groups make long weekly logs easier to read, and it adds
little risk, since it comes from the `tox-dev` organization, like tox
itself. Its
mapping goes in `[tool.tox.gh.python]` in `pyproject.toml`. tox-gh
does nothing outside GitHub Actions, and without it, `tox config`
only adds a note that `gh` is unused. The job sets
`TOX_GH_MAJOR_MINOR` to the matrix version, as tox-gh documents for
when tox runs on a different Python.

`actionlint`, `zizmor` 1.31.1 (pedantic, with online audits), and
`pinact run --check --verify-comment` report nothing for the new
workflow, and all pre-commit hooks pass. With `GITHUB_ACTIONS=true`
set locally, tox with tox-gh ran only `py38` for
`TOX_GH_MAJOR_MINOR=3.8`, in its own log group, and set up `py313`,
`ruff`, `format`, `mypy`, `html`, and `misc` for 3.13. The workflow
itself has not run on GitHub yet, because `workflow_dispatch` and
`schedule` only work once it is on the default branch.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>