[Feature]: Fixed versions of black and ruff in CI

[stefan-it]

Problem statement

Hi everyone,

I was using latest black and ruff locally and it changed some files that I definitely not touched/changes.

Then I could also see test failures of my two recent PRs.

Maybe we should pin a specific version of both black and ruff to avoid this in future.

Before a new release of Flair we could just use the latest versions of them, perform tree-wide reformating and then update the pinned versions again.

What do you think?

[alanakbik]

Yes, pinning the version makes sense!

[stefan-it]

I installed Flair in fresh new virtual environment and used the versions for black and pytest-ruff after installing all dependencies from requirements.txt and requirements-dev.txt.

Tree-wide re-formatting is also applied and result can be seen in #3423. This should us give a green CI hopefully soon :)