Add Linting Github Action

[bytewife]

trafficstars

Linting should improve maintainability by removing classes of errors down the line, and make contributions more standardized

[jmschrei]

We should probably aim to set up a GitHub action in the style of this one which does linting and runs unit tests on a variety of Python versions and OSs: https://github.com/jmschrei/pomegranate/blob/master/.github/workflows/python-package.yml