[MNT] pre-commit updates

[satvshr]

fixes #704
Follows closely with 77 from aiondemand/aiondemand

Only real changes made were:

• .flake8 deletion and replacement with ruff, they both lint (.flake8 being slower, it was also NOT a part of pre-commit), and all operations being provided by .flake8 were moved to ruff.
• Removed pytest passing for all tests before pre-commit given it can slow pre-commit down by a lot and is also not the norm in other repos I have worked on (including openml-python).
• Added .ruff-cache to .gitignore.
• Updated pre-commit versions.
• Changed CI to check for file changes.
• Included tests for ruff checks.
• Removed mypy.

Most changes are due to file endings being changed to LF

[geetu040]

Looks good to me overall

One thing to keep in mind: since it runs only on changed files, even a small tweak in a file will require that file to pass all pre-commit checks. That's probably fine for new PRs, but it could mean some extra cleanup when touching older files. Hopefully it won't create too much overhead in practice.

@fkiraly please take a look and merge.

[fkiraly]

There are some conflicts to resolve, can you kindly have a look?

[satvshr]

Solved, kindly merge sooner rather than later to avoid conflicts