Set up PyPI workflow

[egrace479]

• Adds the workflow for automated publication on PyPI on release (@Andrey170170, add your token, named PYPI_API_TOKEN)
• Updates instructions to pip install from PyPi
• Added keywords noted in Version/Package #28
• Adds python version specifications from Update python dependencies #27

Currently pending #23.

[egrace479]

Should we also add the development status classifier "Development Status :: 4 - Beta",? I think that would be a reasonable way to address current concerns. We're at 0.1.0-alpha right now, so I think upping to 0.2.0-beta with the dev status indicator (I can add the badge to the README) would be reasonable since we're waiting for stability to release v1.0.0, which would be Development Status :: 5 - Production/Stable.

I will also update __about__.py accordingly.

[thompsonmj]

If the PyPI token is added and trusting the deps updates are good