COMP: Fix sphinx documentation build due to breaking change in markdown

This commit workarounds backward incompatible change introduced in
Markdown 3.4 through Python-Markdown/markdown@659a43659 (Update th/td
to use style attribute)

It addresses error like the following:

  Extension error (sphinx_markdown_tables):
  Handler <function process_tables at 0x7f12fd69dc20> for event 'source-read' threw an exception (exception: __init__() missing 1 required positional argument: 'config')

See ryanfox/sphinx-markdown-tables#36
and https://python-markdown.github.io/change_log/release-3.4/

requirements-docs.txt

@@ -5,6 +5,7 @@ myst-parser
 pygments
 sphinx
 sphinx-issues
-sphinx-markdown-tables
+# Workaround for https://github.com/ryanfox/sphinx-markdown-tables/issues/36
+git+https://github.com/Dzordzu/sphinx-markdown-tables.git@3bc0849cf6dc0e1b7fe52aafadc2e2ccca698a01
 sphinx-notfound-page
 sphinx_rtd_theme>=0.5.2