GitHub Action: Allow reading version from pyproject.toml

[srittau]

Description

This adds an use_pyproject input to the GitHub Action that – when set to true – will read the black version from pyproject.toml file. Either from the project.dependencies array or one of the arrays from the project.optional-dependencies table.

Closes: #4285

Checklist - did you ...

• Add an entry in CHANGES.md if necessary?
• Add / update tests if necessary?
• Add new / update outdated documentation?

Trial runs at: https://github.com/srittau/python-asserts/actions/runs/8490172420, using this branch of one of my projects: https://github.com/srittau/python-asserts/tree/black-test

[JelleZijlstra]

Can we look for required-version in the tool.black table first? https://black.readthedocs.io/en/stable/usage_and_configuration/the_basics.html#required-version

That seems better than attempting to parse the dependency metadata.

[hugovk]

Docs nits.

[JelleZijlstra]

Thanks! Could you also add a changelog entry?

[srittau]

Thanks! Could you also add a changelog entry?

How to best do this? This doesn't really fit the existing structure of the CHANGES file, as this is independent of the versions of black.

[JelleZijlstra]

Thanks! Could you also add a changelog entry?

How to best do this? This doesn't really fit the existing structure of the CHANGES file, as this is independent of the versions of black.

It can go in the "Integrations" section (https://github.com/psf/black/blob/main/CHANGES.md#integrations). The Actions version is a little disconnected, but for most people the change should still become useful when we make our next release.