Run unit tests across Python versions 3.10-3.12.

[ScottTodd]

Also updated enough of the project to pass these new test configurations:

• Avoid starred expressions in indexes for Python < 3.11 (https://stackoverflow.com/a/77080166, https://stackoverflow.com/q/77580216)
• Import Self from typing_extensions for Python < 3.11 (https://stackoverflow.com/a/77247460)
• Limit use of logger.getLevelNamesMapping to Python >= 3.11 (https://docs.python.org/3/library/logging.html#logging.getLevelNamesMapping, see also https://mypy.readthedocs.io/en/stable/common_issues.html#python-version-and-system-platform-checks)
• Stop using unittest in files that don't need it, fixing exit code 5 in Python >= 3.12 for "no tests were run" (https://docs.python.org/3/library/unittest.html#unittest.main)

[ScottTodd]

@marbre you may have opinions on the job naming. I'm not sure about this.

BTW, type checking does make sense to run on multiple python versions. The use of logging.getLevelNamesMapping() # Added in 3.11 was caught by running mypy on 3.10. I originally wanted to move type checking to pre-commit since it's similar to other lint checks, but I now think it makes sense to keep it here

[marbre]

Following the naming in other repos we would have "Unit Tests and Type Checking :: ${{ matrix.os }} :: ${{ matrix.version }}" but to be honest I don't really care and if we start to dislike we can change it in the future. Thus I don't want to be picky here 😉

[ScottTodd]

Yeah I'd like to put important information at the start of the name so it doesn't get cut off

• 
• 

[marbre]

Works for me :)

[marbre]

Looks good and is a nice improvement!

[marbre]

Following the naming in other repos we would have "Unit Tests and Type Checking :: ${{ matrix.os }} :: ${{ matrix.version }}" but to be honest I don't really care and if we start to dislike we can change it in the future. Thus I don't want to be picky here 😉

[ScottTodd]

Argh GitHub. This was also being used for a required check matching Unit Tests and Type Checking (3.11, ubuntu-22.04), but that check is actually picking up TK CI / Unit Tests and Type Checking (3.11, ubuntu-22.04) also.

I might just copy this snippet from IREE to have a "ci-summary" job with a unique name we can set as required: https://github.com/iree-org/iree/blob/7177c29f9b2d9e255b63987f5dfff174ec2afc2f/.github/workflows/ci.yml#L201-L236