Run mypy against several pip and Python versions

[atugushev]

It might be useful to run mypy against several pip and Python versions (like min + max). Just the last one isn't going to cover a lot of stuff..

Originally posted by @webknjaz in #1927 (comment)

[chrysle]

I guess we could use ansible-community/sphinx_ansible_theme@e86ef32 as a reference.

[webknjaz]

That should do.