Merge branch 'master' into requires-io-master

Author: wsanchez

tox.ini

@@ -318,7 +318,7 @@ description = build documentation
 basepython = {[default]basepython}
 
 deps =
-    Sphinx==3.1.1
+    Sphinx==2.4.4
     sphinx-rtd-theme==0.5.0
 
 commands =