Merge pull request #761 from VWS-Python/dependabot/pip/sphinx-substitution-extensions-2020.9.30.0

Bump sphinx-substitution-extensions from 2020.7.4.1 to 2020.9.30.0

Author: adamtheturtle

dev-requirements.txt

@@ -1,5 +1,5 @@
 PyYAML==5.3.1
-Sphinx-Substitution-Extensions==2020.7.4.1
+Sphinx-Substitution-Extensions==2020.9.30.0
 Sphinx==3.2.1
 VWS-Test-Fixtures==2020.9.25.1
 attrs==20.2.0  # Modern attrs is required for pytest