CI failing for 3.10 and 3.11

[hugovk]

For example:

2025-04-18 09:47:53,730 ERROR en/3.11: Run: '/home/runner/work/python-docs-theme/python-docs-theme/build_root/venv-3.11/bin/python -m pip install --upgrade --upgrade-strategy=eager /home/runner/work/python-docs-theme/python-docs-theme -rrequirements.txt jieba 'PyStemmer~=2.2.0' 'matplotlib>=3'' KO:
      Downloading blurb-2.0.0-py3-none-any.whl.metadata (9.1 kB)
    Collecting sphinx-autobuild (from -r requirements.txt (line 13))
      Downloading sphinx_autobuild-2024.10.3-py3-none-any.whl.metadata (7.7 kB)
    Collecting sphinxext-opengraph==0.7.5 (from -r requirements.txt (line 14))
      Downloading sphinxext_opengraph-0.7.5-py3-none-any.whl.metadata (6.2 kB)
    Collecting sphinx-notfound-page==1.0.0 (from -r requirements.txt (line 15))
      Downloading sphinx_notfound_page-1.0.0-py3-none-any.whl.metadata (2.9 kB)
    INFO: pip is looking at multiple versions of python-docs-theme to determine which version is compatible with other requirements. This could take a while.
    ERROR: Cannot install python-docs-theme==20[25](https://github.com/python/python-docs-theme/actions/runs/14533257515/job/40776866509#step:6:26).2 and sphinx~=7.2.0 because these package versions have conflicting dependencies.
    
    The conflict is caused by:
        The user requested sphinx~=7.2.0
        python-docs-theme 2025.2 depends on sphinx>=7.3
    
    To fix this you could try to:
    1. loosen the range of package versions you've specified
    2. remove package versions to allow pip to attempt to solve the dependency conflict
    
    ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/topics/dependency-resolution/#dealing-with-dependency-conflicts
    
2025-04-18 09:47:53,741 ERROR en/3.11: Badly handled exception, human, please help.
Traceback (most recent call last):
  File "/home/runner/work/python-docs-theme/python-docs-theme/./docsbuild-scripts/build_docs.py", line 577, in run
    self.build_venv()
    ~~~~~~~~~~~~~~~^^
  File "/home/runner/work/python-docs-theme/python-docs-theme/./docsbuild-scripts/build_docs.py", line 706, in build_venv
    run(
    ~~~^
        (
        ^
    ...<9 lines>...
        cwd=self.checkout / "Doc",
        ^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/home/runner/work/python-docs-theme/python-docs-theme/./docsbuild-scripts/build_docs.py", line [33](https://github.com/python/python-docs-theme/actions/runs/14533257515/job/40776866509#step:6:34)6, in run
    result.check_returncode()
    ~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/opt/hostedtoolcache/Python/3.13.3/x64/lib/python3.13/subprocess.py", line 508, in check_returncode
    raise CalledProcessError(self.returncode, self.args, self.stdout,
                             self.stderr)
subprocess.CalledProcessError: Command '['/home/runner/work/python-docs-theme/python-docs-theme/build_root/venv-3.11/bin/python', '-m', 'pip', 'install', '--upgrade', '--upgrade-strategy=eager', '/home/runner/work/python-docs-theme/python-docs-theme', '-rrequirements.txt', 'jieba', 'PyStemmer~=2.2.0', 'matplotlib>=3']' returned non-zero exit status 1.

https://github.com/python/python-docs-theme/actions/runs/14533257515/job/40776866509

Failed before, but showed up as green:

https://github.com/python/python-docs-theme/actions/runs/14428653230/job/40460802134#step:6:32

Recent changes in docsbuild-scripts mean failures do fail: python/docsbuild-scripts#286.

[AA-Turner]

We should drop 3.10/11, they're pinned and won't get further backports: https://github.com/python/cpython/blob/3.11/Doc/requirements.txt