Update black version in setup.cfg and pyproject.toml

[dnth]

Updating black version throughout the repo. black==20.8b1 throws an error like the following:

Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.7.13/x64/bin/black", line 8, in <module>
    sys.exit(patched_main())
  File "/opt/hostedtoolcache/Python/3.7.13/x64/lib/python3.7/site-packages/black/__init__.py", line 6606, in patched_main
    patch_click()
  File "/opt/hostedtoolcache/Python/3.7.13/x64/lib/python3.7/site-packages/black/__init__.py", line 6595, in patch_click
    from click import _unicodefun  # type: ignore
ImportError: cannot import name '_unicodefun' from 'click' (/opt/hostedtoolcache/Python/3.7.13/x64/lib/python3.7/site-packages/click/__init__.py)
Error: Process completed with exit code 1.

Error goes away with black==22.3.0.

More info https://stackoverflow.com/questions/71673404/importerror-cannot-import-name-unicodefun-from-click

[dnth]

Hitting a roadblock here because

keras-autodoc 0.6.0 depends on black==20.8b1