It had been broken by 36a6d2c6.

* Version 3.0.0

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci



---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

updates:
- [github.com/pre-commit/pre-commit-hooks: v4.4.0 → v4.5.0](https://github.com/pre-commit/pre-commit-hooks/compare/v4.4.0...v4.5.0)
- https://github.com/charliermarsh/ruff-pre-commit → https://github.com/astral-sh/ruff-pre-commit
- [github.com/astral-sh/ruff-pre-commit: v0.0.275 → v0.0.292](https://github.com/astral-sh/ruff-pre-commit/compare/v0.0.275...v0.0.292)
- [github.com/psf/black: 23.3.0 → 23.9.1](https://github.com/psf/black/compare/23.3.0...23.9.1)
- [github.com/pre-commit/mirrors-mypy: v1.4.1 → v1.5.1](https://github.com/pre-commit/mirrors-mypy/compare/v1.4.1...v1.5.1

)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

updates:
- [github.com/charliermarsh/ruff-pre-commit: v0.0.272 → v0.0.275](https://github.com/charliermarsh/ruff-pre-commit/compare/v0.0.272...v0.0.275)
- [github.com/pre-commit/mirrors-mypy: v1.3.0 → v1.4.1](https://github.com/pre-commit/mirrors-mypy/compare/v1.3.0...v1.4.1

)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

updates:
- [github.com/charliermarsh/ruff-pre-commit: v0.0.270 → v0.0.272](https://github.com/charliermarsh/ruff-pre-commit/compare/v0.0.270...v0.0.272

)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

In particular:
 * use def rather than assigning lambda function
 * unused imports
 * 'X not in Y' vs 'not X in Y'

An example of this is e.g. EUC-TW

In some cases, it seems to find an encoding that's not valid for the
entire string.

* Docker image: Fix ownership issue with Git 2.36+

* Update tests.yml

Add pyproject.toml.

Handle SymrefLoop. Fixes: #293