Add CI builds & publish

[mathieugouin]

Hi,

Thanks for your great library. I saw it is not on pypi yet.

I thought I could help.

I added 2 ci workflows:

• one to build at every push, so we can check if nothing is broken
• one to publish to pypi on release. This one I did not try. You will probably have to tweak it to provide the proper token.

Thanks!