feat: use SPEC 0 schedule for cibuildwheel

[mayeut]

As discussed in various issues, I think that cibuildwheel is in position where it might make sense to follow SPEC 0 schedule rather than the CPython schedule. This would allow to take advantage of new Python features faster (or without/ with less back ports).

This draft PR is:

• to gather feedback on such a change
• to check that indeed, every CI we support is ready.
• preview what would change
• if we want to follow-up with this, then, it might be a good thing to warn users ahead to let them update there workflows if need be (mostly for CI that do not come with python pre-installed).

The idea would be to switch to SPEC 0 in 2024Q4 after Python 3.8 EOL & Python 3.13 GA, thus dropping 3.8, 3.9 & 3.10.

[mayeut]

Suggested change

allow-prereleases: true

To be removed once 3.13 reaches GA

[joerick]

I support this change. There is very little reason to hang on to older Pythons on the host side, when we can benefit from new features.

To be clear to anyone coming across this, we're talking about the version of Python that is used to run cibuildwheel. That is distinct from the versions of Python that we build wheels for, which would be unchanged by this.

[EwoutH]

I think it's very logical for a project like cibuildwheel to follow SPEC 0 on the host side.