First, fix test_help(). A commit[1], which first appeared in Python
3.10, changes the output of the help feature of argparse. Options used
to be in a section named "Optional arguments:", and they are now in a
section named "Options:".
Second, tox 4 changes the behaviour of tox, and
{toxinidir}/requirements.txt is no longer installed automagically in the
docs virtual environment. This causes autodoc to fail on some imports.
We explicitely add {toxinidir}/requirements.txt to the list of
dependencies to fix this issue.
These issues should be fixed in separate patches, but since they both
block the CI, they depend on each other.
[1] https://github.com/python/cpython/pull/23858
Change-Id: Ia7866390b31f469bdea95624325a13aaf45a496e
Closes-Bug: #2002566
6c95122777