Restore CI

[rshk]

Looks like travis CI discontinued their free plan, as a result CI hasn't been running.
We should probably migrate to an alternative (CircleCI / GitHub actions?)

[bbenne10]

GitHub actions should be a simple enough, I think?
https://github.com/marketplace/actions/run-pytest and https://github.com/actions/starter-workflows/blob/main/ci/python-package.yml show off python runners.