Drop support for Python 3.10

[hugovk]

Python 3.10 reaches end of life in October 2026:

• https://peps.python.org/pep-0619/

Pillow 13.0.0 is planned for 2026-10-15 and will drop Python 3.10:

• https://github.com/python-pillow/Pillow/milestone/66

TODO:

• Rebase after Remove deprecations for Pillow 13.0.0 #9751
• Update Python to 3.11 in CentOS Stream 9: python-pillow/docker-images#274
• Decide about ubuntu-22.04-jammy-amd64 and ubuntu-22.04-jammy-amd64-valgrind which use 3.10: upgrade to 3.11 or drop

[hugovk]

Decide about ubuntu-22.04-jammy-amd64

Let's remove that one, we did the same two years ago for 20.04: python-pillow/docker-images#275.

and ubuntu-22.04-jammy-amd64-valgrind which use 3.10: upgrade to 3.11 or drop

I think it's time for the slower ubuntu-24.04-noble-amd64-valgrind: python-pillow/docker-images#272.

[hugovk]

Similar to radarhere/docker-images#4, I've split the valgrind tests into four jobs.

Workflow	22.04 unsplit (main)	24.04 unsplit	24.04 split x 4
Test Valgrind	81m - 89m	99m	36m
Test Valgrind Memory Leaks	3h 08m - 3h 40m	3h 07m	54m

[hugovk]

Also added:

• https://docs.python.org/3/whatsnew/3.11.html#pep-655-marking-individual-typeddict-items-as-required-or-not-required
• https://docs.python.org/3/whatsnew/3.11.html#warnings