Test opaque-keys on Python 3.11

[feanil]

This repository is a depedency of edx-platform and needs to be upgraded to Python 3.11 before the Readwood release is cut (mid-April).

• [x] Requirements are compiled with Python 3.8
• [x] Tests are run on Python 3.8 and 3.11
• [ ] (Optional) Tests are also run with 3.12 and passing or 3.12 issues are ticketed.
• [x] Classifiers in setup.py setup.cfg or pyproject.toml indicate Python 3.11 support
• [x] A new version is release to PyPI
• [x] A PR is merged to edx-platform to use the new version