Merge pull request readthedocs#89 from readthedocs/pyup/scheduled-update-2020-08-31

pyup:  Scheduled weekly dependency update for week 35

Author: humitos

docs/requirements.txt

@@ -5,4 +5,4 @@ sphinx-tabs==1.2.1
 sphinx-prompt==1.1.0
 sphinx-version-warning==1.1.2
 sphinx-notfound-page==0.5
-sphinx-autobuild==0.7.1
+sphinx-autobuild==2020.9.1