Address ci deprecations

[titodalcanton]

I noticed a couple recent deprecations related to our CI tests. This should address them.

One is the version of Ubuntu: actions/runner-images#11101.

The other one is the Python version used to build the distribution workflow:

cibuildwheel 3 will require Python 3.11+, please upgrade the Python version used to run cibuildwheel. This does not affect the versions you can target when building wheels. See: https://cibuildwheel.pypa.io/en/stable/#what-does-it-do

• The author of this pull request confirms they will adhere to the code of conduct

[titodalcanton]

Hmm, some of the tests are failing, apparently due to this:

2025-03-16T16:30:43.3635028Z Traceback (most recent call last):
2025-03-16T16:30:43.3661816Z   File "/home/runner/work/pycbc/pycbc/examples/live/./check_results.py", line 14, in <module>
2025-03-16T16:30:43.3662633Z     from ligo.skymap.io import LigoLWEventSource
2025-03-16T16:30:43.3663615Z   File "/home/runner/work/pycbc/pycbc/.tox/py-search/lib/python3.9/site-packages/ligo/skymap/io/__init__.py", line 9, in <module>
2025-03-16T16:30:43.3664666Z     exec('from . import {0};'
2025-03-16T16:30:43.3665056Z   File "<string>", line 1, in <module>
2025-03-16T16:30:43.3665947Z   File "/home/runner/work/pycbc/pycbc/.tox/py-search/lib/python3.9/site-packages/ligo/skymap/io/fits.py", line 70, in <module>
2025-03-16T16:30:43.3666771Z     from .. import moc
2025-03-16T16:30:43.3667526Z   File "/home/runner/work/pycbc/pycbc/.tox/py-search/lib/python3.9/site-packages/ligo/skymap/moc.py", line 36, in <module>
2025-03-16T16:30:43.3668500Z     from .core import nest2uniq, uniq2nest, uniq2order, uniq2pixarea, uniq2ang
2025-03-16T16:30:43.3669761Z ImportError: /home/runner/work/pycbc/pycbc/.tox/py-search/lib/python3.9/site-packages/ligo/skymap/core.abi3.so: undefined symbol: gsl_root_fdfsolver_steffenson

I am going to try a less aggressive update to ubuntu-22.

Edit: I suspect this is due to ligo.skymap no longer supporting Python 3.9. If this is the case, we should be able to go all the way to ubuntu-24 once we drop the 3.9 tests.

[titodalcanton]

The Mac tests were also failing, but they are passing after clearing the CI cache.

[GarethCabournDavies]

I see no issues, and the CIs are passing

[titodalcanton]

It seems the branch protection rules are somehow bound to the old versions of the tests, which will not run anymore. I guess I will temporarily remove those requirements, merge this, and then re-enable them with the new tests.