PyPI claims Python 3.9 is supported
This requirement is incorrect: https://gitlab.com/meltano/meltano/-/blob/8034a24b2f3aa8eb76e132590627b07a5c2809e2/pyproject.toml#L20
3.9 is not actually supported yet: https://meltano.com/docs/installation.html#python-3-6-3-7-or-3-8