Merge pull request #1053 from adafruit/dhalbert-patch-1

update ReadTheDocs build to ubuntu-lts-latest and general Python 3, not a specific python version

Author: makermelissa

.readthedocs.yaml

@@ -12,9 +12,9 @@ sphinx:
   configuration: docs/conf.py
 
 build:
-  os: "ubuntu-20.04"
+  os: "ubuntu-lts-latest"
   tools:
-    python: "3.7"
+    python: "3"
   apt_packages:
     - python3-dev