Bump sphinx from 2.4.3 to 2.4.4 in /docs (#158)

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 2.4.3 to 2.4.4.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/3.x/CHANGES)
- [Commits](sphinx-doc/sphinx@v2.4.3...v2.4.4)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

docs/requirements.txt

@@ -1,7 +1,7 @@
 # This file is used to setup env
 # to generate documentation.
 
-sphinx==2.4.3
+sphinx==2.4.4
 sphinx_autodoc_typehints==1.10.3
 recommonmark==0.6.0
 m2r==0.2.1