Tox is a test runner for Python: https://tox.wiki/en/latest/
For now, we're going to use it to run pre-commit, and as a front-end for GitHub actions; later, when we have actual tests, we will use tox to run these too.

• Install tox: https://tox.wiki/en/latest/installation.html
• Create a tox.ini file in project root
• Add config to tox.ini to run pre-commit (similar to https://github.com/mediawiki-utilities/python-mwsql/blob/main/tox.ini)
• Move flake8's config to tox.ini and delete .flake8
• Run tox to make sure everything is working