Remove support for Python 3.10

[dangunter]

EOL is Oct 2026 (https://devguide.python.org/versions/)

[blnicho]

I vote we wait until the first release after Oct 2026 to remove Python 3.10 support. This is the policy we use for Pyomo: https://pyomo.readthedocs.io/en/stable/contribution_guide.html#python-version-support