Add changelog checker

[ClementPinard]

Pull Request

Describe your changes

Add changelog Checker action that fails when a PR is submitted without change in the CHANGELOG.md

The action is not run if the PR is labelled "dependencies" so that dependabot and pre-commit PR won't fail.

I have deliberately left the CHANGELOG untouched to see how the action would behave.

Issue number if applicable

Checklist before requesting a review

Github actions will check that these tasks were performed but it will reduce friction if you deal with them beforhand

• If code is added, the new lines are covered by tests (Checked by Codecov)
• Type hints are consistent (Checked by pyright Job)
• Code style follows black conventions (Checked by pre-commit)
• If documentation is added, it does not raise a warning in sphinx (checked by sphinx-build)
• CHANGELOG has been updated if applicable

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

[ClementPinard]

PR on hold for the moment, as no satisfying actions can be found.

I created an issue for the most promising one, because it lets you chose which label to ignore and posts a comment afterward, but right now outputs a syntaxe error

GiulioRomualdi/yet-another-changelog-checker#1