Update .readthedocs.yaml

.readthedocs.yaml

@@ -5,12 +5,17 @@
 # Required
 version: 2
 
+# Set the version of Python and other tools you might need
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.9"
+
 # Build documentation in the docs/ directory with Sphinx
 sphinx:
   configuration: docs/conf.py
 
 # Optionally set the version of Python and requirements required to build your docs
 python:
-  version: 3.9
   install:
     - requirements: docs/requirements.txt