Fix GitHub Actions running in a PR by setting the correct branch

[tleonhardt]

The primary fix here is to change the branch name in .github/workflows/test.yaml from master to main.

However a general attempt at modernizing the overall CI/CD has been made.

Changes include:

• Added .pre-commit-config.yaml and prek to automate checks easily locally via pre-commit hooks
• Bumped minimum Python version to 3.10 as this is now the minimum supported
• Added support for Python 3.14 and free-threaded variant
• Added a Makefile to make local development a little easier
• Added various dependency_groups to pyproject.toml

Closes #2056

[tleonhardt]

@jonathanslenders Hi Jonathan, thanks for creating an awesome library!

The main point of this PR is to fix the GitHub Actions running in a PR - it appears to have broken at some point when the default branch was renamed from master to main.

I took the liberty of providing a lot of other modernization in the process. If there is anything you don't agree with, please let me know and I'll be happy to roll that back.

[tleonhardt]

@jonathanslenders Thanks for all of your great feedback. I think I've addressed all of your comments so far other than deleting the .pre-commit-config.yaml and Makefile. I'm personally a huge fan. But if you don't like them I'll remove those as well and if you are cool with it add them to the .gitignore so I can leave them on my machine.

But if you haven't tried it out before, I'd recommend giving the workflow a try. Prior to commits I'm accustomed to doing:

make check
make docs
make test

It lets me hop back and forth between projects without having to worry about the details of how to build documentation, run tests, and do quality checks for each project.

[tleonhardt]

I deleted the Makefile and added that to the .gitignore. I think I have addressed all existing comments, including restoring the inadvertently deleted comments.

Please let me know if there are any other changes you would like.

[jonathanslenders]

@tleonhardt: Thanks! All looks great now! I'll have a second look tomorrow with a fresh mind right before merging. (Just want to be sure not to miss anything.)