Fix readthedocs config format key

dmacvicar · dmacvicar · commit 8f21b0bc26b1 · 2019-10-09T17:06:09.000+02:00
diff --git a/.readthedocs.yml b/.readthedocs.yml
@@ -10,7 +10,8 @@ sphinx:
   configuration: docs/conf.py
 
 # Optionally build your docs in additional formats such as PDF and ePub
-formats: html
+formats:
+  - html
 
 # Optionally set the version of Python and requirements required to build your docs
 python:
