Merge pull request #1140 from adamtheturtle/pyup-update-sphinx-2.3.0-to-2.3.1

Update sphinx to 2.3.1

Author: adamtheturtle

dev-requirements.txt

@@ -3,7 +3,7 @@
 PyYAML==5.2
 Pygments==2.5.2
 Sphinx-Substitution-Extensions==2019.6.15.0
-Sphinx==2.3.0
+Sphinx==2.3.1
 VWS-Python-Mock==2019.12.17.0
 VWS-Test-Fixtures==2019.12.13.1
 autoflake==1.3.1