Handle verbosity argument to obtain in pip 22.x + fix CI

[matteius]

New version of pip requires a verbosity argument and pip-shims has already updated to support it:
sarugaku/pip-shims#79

This will support pipenv: https://github.com/pypa/pipenv/pull/4969/files

Includes cleanup to get CI passing. Notable:

• setuptools is taking steps towards distlib removal, and so import order matters now to continue as-is.
• Python 3.6 is dead and the test for requests master was failing, so I removed support. Noting here that the code likely still works for python 3.6, but users shouldn't expect that trend to continue.
• Pin pyparsing < 3.0.0 to give us time to investigate two test failures related to parsing system markers in the 3.x series.

[oz123]

I wonder if the quotes around 3.10 are necessary. But you didn't do it, so it does not matter so much.

[frostming]

It does, it is a common quirk of yaml, 3.10 will be parsed as 3.1(float). In fact all 3.x if not quoted, are parsed as floats, but only 3.10 changes the meaning.