Update build system to pyproject.toml

[alexfikl]

This makes two changes:

• Updates the build system to use pyproject.toml
• Adds a CI using Github Actions to test that everything works on all the supported versions.

Unfortunately, the build system changes seem to require bumping the minimum python version. setuptools v64.0 (the first one that supports pyproject.toml configuration) requires Python >=3.7. The currently maintained Python versions are >=3.9 though (Python 3.8 went in October 2024).

Also, the CI changes won't take effect until they're actually merged to master, so not very helpful to see if they work now. Let me know how you want to handle things and however I can help! 😁

[Wrzlprmft]

Thank you for tackling this. Unfortunately, this pull request came at an inopportune moment. Given that I need check some things myself, as you noticed, it will take a bit more till I can get to it.

[alexfikl]

Thank you for tackling this. Unfortunately, this pull request came at an inopportune moment. Given that I need check some things myself, as you noticed, it will take a bit more till I can get to it.

That's not a problem at all! They're more of a quality of life sort of changes, so not urgent in any way.

[Wrzlprmft]

So, I merged this and there seems to be a syntax problem with the CI file. Unfortunately the error message is not very informative. I would have to either continue with trial and error or figure out some way to test these files outside a live repository.

[alexfikl]

So, I merged this and there seems to be a syntax problem with the CI file. Unfortunately the error message is not very informative. I would have to either continue with trial and error or figure out some way to test these files outside a live repository.

Oops! Sorry for not checking that better. #6 should address that (as soon as I make the 3.6 run work).