Adding wheels for a new Python release

• Update Git main
  • git checkout main
  • Add classifier for new Python version to setup.py
  • Add new Python version to lists in .github/workflows/python.yml
  • Commit and open a PR
  • Merge the PR when CI passes
  • Add new Python jobs to branch protection required checks
• Build new wheels
  • Check out a new branch from the most recent release tag
  • Add new Python version to lists in .github/workflows/python.yml, commit, and open a DNM PR
  • Find the workflow run for the PR; download its wheels artifact
  • Close the PR
• In OpenSlide Python checkout, git checkout v<version> && git clean -dxf && mkdir dist
• Copy downloaded wheels from new Python release only into dist directory
• twine upload dist/*
• Upload new wheels to GitHub release
• Update MacPorts package
• Update website: Python 3 versions in download/index.md - Release Windows build 20230414; update MacPorts to Python 3.11 openslide.github.io#38