python3-saml2: update to 6.4.1.

[ndowens]

This fixes byte-compiling upon install

[ericonr]

Oops, it hadn't been merged yet #26901

[ahesford]

tox is generally disfavored because it doesn't actually test against the contents of the package and the Void-packaged dependencies. It creates a virtualenv and populates it with pip, then tests that.

For pytest, you need to make sure all dependencies are available, plus a couple of extras just for testing. We don't package a couple of these, so you have to ignore tests that require thigns we don't provide. You also need, in this case, to set PYTHONPATH=src because the project package are inside this subdirectory (you could also use build/lib* to get the staged package created by setuptools).

See e285453 for more information.