Update of some requirements versions.

[aknrdureegaesr]

You can now in all requirements files replace the '>=' with '==', pip will install this, and the tests will succeed.

Pull Request Checklist

• I’ve read the guidelines for contributing.
• I updated AUTHORS.txt and CHANGES.txt (if the change is non-trivial) and documentation (if applicable). Not applicable.
• I tested my changes.

Description

This pertains to #3734. It is some improvement on the previous state of our dependencies. This PR presents a set of minimal versions that makes the test succeed.

Extensive running of some one-off script is at the base of this. The script mixes dependency versions, tries to throw the combination at pip, and, in case that succeeds, tries to run pytest. Code coverage was switched off during the pytest runs for performance. (Is that script wanted? I can contribute it.)

The versions come from some pip freeze --all output. So you can replace all >= in the requirements files with == and throw the result at pip: The pip run will succeed and so will a pytest run in that venv.

But this really only pertains the tests. And the Nikola tests apparently don't test everything.

How do I know? With my venv with all == as described, I tried to build nikola-site with nikola auto -b and that failed, I believe when the first rebuild was asked for after editing. I started a feeble attempt to get that going by timid updates, one such update is included, but gave up on the second problem.