add flake8 python version check script and CI check

[r-downing]

from #365

Made a quick standalone python script. Uses curl (so no need to pip install requests or anything else) to get pypy json info for flake8. Grabs the requires-python = ... line from pyproject.toml and compares the two, will throw an error if they don't match.

Note - chose to get bugbear version from pyproject.toml rather than fetching bugbear json because then the test would fail until a bugbear update was uploaded to pypi.

Not sure about naming or folder placement - just stuck it in a scripts folder.

Testing:

Made it run on push, and changed the python version in pyproject.toml to see it fail. Sample error output

error output:

Run python scripts/flake8_py_version_check.py
Traceback (most recent call last):
  File "/home/runner/work/flake8-bugbear/flake8-bugbear/scripts/flake8_py_version_check.py", line 3[4](https://github.com/r-downing/flake8-bugbear/actions/runs/7041812391/job/19164955564#step:3:5), in <module>
    main()
  File "/home/runner/work/flake[8](https://github.com/r-downing/flake8-bugbear/actions/runs/7041812391/job/19164955564#step:3:9)-bugbear/flake8-bugbear/scripts/flake8_py_version_check.py", line 2[9](https://github.com/r-downing/flake8-bugbear/actions/runs/7041812391/job/19164955564#step:3:10), in main
    flake8_requires == flake8_bugbear_requires
AssertionError: python version requirements don't match: (flake8_requires='>=3.8.1' != flake8_bugbear_requires='>=3.8.0')

Fixes #365

[cooperlees]

Thanks. I like not having to check and be able to be lazy. This is all good to me but offered some suggestions. If you don't want to spend time doing them, that's fine, just say so and I'll do them one day.

• I don't like to block merging on nit picks / nice to haves :)
  • especially on simple scripts like this :)

[cooperlees]

Thankyou for the verbose assert failing message :)