I don't think it's needed. I'm not building a universal wheel (2/3
compatible) and the license file is already mentioned in
`pyproject.toml`. Let's see what the CI says.

Allow for editable installation (at least with some combination of
packages because locally I can install it fine without it).

The version of Setuptools that has pyproject.toml/ PEP 621 support
requires Python 3.7 or later (supported version of Python).

My Python pipeline template is more conservative (still on Python 3.6
and Centos 7 for backwards compatibility). Redo it with a newer Python
image.

- pre-commit config.
- CI pipeline to build the package, validate with twine, install it and
  check the executable script.
- Add a badge to the README.

Just the package and a main function.

README, license and .gitignore.