use Python 3.6 for docs build

miguelgrinberg · miguelgrinberg · commit 142e47873757 · 2017-03-08T19:14:14.000-08:00
diff --git a/.readthedocs.yml b/.readthedocs.yml
@@ -0,0 +1,3 @@
+python:
+  version: 3.6
+  setup_py_install: true
