Readthedocs does not support python 3.7

LefterisJP · palango · commit bec0d5cc4c87 · 2019-02-05T15:29:40.000+01:00
Issue is [here](readthedocs/readthedocs.org#4713). [skip tests]
diff --git a/readthedocs.yml b/readthedocs.yml
@@ -2,4 +2,4 @@ build:
     image: latest
 
 python:
-    version: 3.7
+    version: 3.6
