Update .readthedocs.yml

Daniel Abercrombie · web-flow · commit 033a345bee91 · 2020-01-02T15:20:37.000-05:00
diff --git a/.readthedocs.yml b/.readthedocs.yml
@@ -8,4 +8,4 @@ formats: all
 python:
   version: 3.7
   install:
-    requirements: docs/requirements.txt
+    - requirements: docs/requirements.txt
