Fix lint issues and add license so CI builds.

[kbsriram]

No description provided.

[dhalbert]

BTW, did you mean to close this? Maybe it was meant for your own repo?

[jepler]

The CI error says:

Warning, treated as error:
autodoc: failed to import module 'adafruit_pio_uart'; the following exception was raised:
No module named 'rp2pio'

The first fix to try for this kind of error building documentation is to edit docs/conf.pyand add the module(s) that could not be imported to the list of "autodoc_mock_imports". In this case, rp2pio. This will allow the documentation building process to pretend rp2pio is importable, but occasionally leads to further errors.

An example of this is: https://github.com/adafruit/Adafruit_CircuitPython_NeoPxl8/blob/main/docs/conf.py#L30

[kbsriram]

Thank you @dhalbert and @jepler ! I'd closed this thinking I'd do some research on the CI issue first, without adding review load on you folks. Thank you for the very helpful hints - I'll re-open and see if I can get a clean build :-)

[FoamyGuy]

I don't have much knowledge of PIO specifically, but I had a look through these changes.

The fixes to lint and other pre-commit checks all look good to me at this point, and the behavior of the looks unchanged to me.

Thanks for working on this @kbsriram