repo:voltha-docs "make html" target fails with python v3.10

REPO: https://gerrit.opencord.org/plugins/gitiles/voltha-docs/+/refs/heads/master

Python deps: https://gerrit.opencord.org/plugins/gitiles/voltha-docs/+/refs/heads/master/requirements.txt

% cd voltha-docs
% make clean-all html

ERROR: ImportError: cannot import name 'Mapping' from 'collections' (/usr/lib/python3.10/collections/_init_.py)

Remove dependency on static /zdw/ python module sphinx-multiversion:

git+https://github.com/zdw/sphinx-multiversion@ec7c01cdaf2f9241245e84483dfb9bc0d0dffc62

Update requirements.txt / pip modules to use newer versions or better yet remove the version dependency altogether:

• sphinx: 5.1.1+
• robotframework 5.1.1+
• doc8
• [...]

Python modules:

• https://pypi.org/project/robotframework/
• latest: 5.0.1
• active: 3.1.2

Bug fix verify:

• makefile targets run cleanly:
• git clone
• make clean-all
• make html