Make Python package detection work with pip 10

pip 10 moved several interfaces to an internal package, causing our pyversion.py script to fail. This patches fixes the issue by getting installed distributions directly from setuptools, as suggested in https://github.com/pypa/pip/issues/5243.

enabled an automatic merge when the pipeline for 2443bc4a succeeds

merged

mentioned in commit 746aa626

mentioned in commit 79906467

mentioned in merge request !541 (merged)

mentioned in merge request !496 (closed)