Merge branch 'dependabot/pip/babel-2.9.0' into 'develop'

Bump babel from 2.8.0 to 2.9.0

See merge request !159

sphinx-doc/requirements_sphinx.txt

 alabaster==0.7.12
 appdirs==1.4.4
 astor==0.8.1
+Babel==2.9.0
 attrs==20.3.0
-Babel==2.8.0
 black==20.8b1
 certifi==2020.11.8
 chardet==3.0.4