RTD: use python 3.9 to overcome problem with napoleon use of collections

yarikoptic · yarikoptic · commit 994180e0bfe7 · 2022-11-03T19:11:28.000-04:00
diff --git a/.readthedocs.yaml b/.readthedocs.yaml
@@ -8,7 +8,7 @@ python:
 build:
   os: ubuntu-20.04
   tools:
-    python: "3"
+    python: "3.9"
 sphinx:
   configuration: docs/conf.py
   fail_on_warning: true
