Update mypy

[kclowes]

What was wrong?

hexbytes wouldn't install dev dependencies with the latest versions of Python.

How was it fixed?

Upgraded mypy, fixed some typing errors, fixed the doc build, fixed a few other misc. things that prevent releasing.

Added lint runs against all supported python versions because they're quick and I think it's a valuable smoke test.

To-Do

• [x] Clean up commit history

• [x] Add entry to the release notes

Cute Animal Picture

[kclowes]

@fselmo This should be ready for one more look when you get a chance please 👀

[fselmo]

I think there's value in having a make lint command for local dev purposes, that runs with whatever python version you are on. So having a lint testenv would be nice to have:

[testenv:lint]
basepython=python
deps={[common-lint]deps}
commands={[common-lint]commands}

[kclowes]

That's a good point. I'll put it back. Thanks!