Update readthedocs.yaml

Another attempt to fix readthedocs config

readthedocs.yaml

@@ -16,9 +16,13 @@ sphinx:
 # Optionally build your docs in additional formats such as PDF and ePub
 formats: all
 
+# Set the OS, Python version and other tools you might need
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.9"
+
 # Optionally set the version of Python and requirements required to build your docs
 python:
-  os: ubuntu-20.04
-  version: 3.9
   install:
     - requirements: docs/requirements.txt