- Test supported numpy versions in CI matrix. Bump minimum numpy from 1.13 to 1.14.
- Update tests to use pytest fixture instead of global variable
- Add `[test]` extras to setup.py
- Use `oldest-supported-numpy` in pyproject.toml. This will make the version built by `pip` compatible with versions of `numpy<=1.20`
- Create ci.yml so we have CI in this repo