readthedocs: fix build issue

.readthedocs.yml

@@ -1,11 +1,15 @@
 version: 2
 
+# Explicitly set os and the version of Python
+build:
+  os: "ubuntu-22.04"
+  tools:
+    python: "3.11"
+
 # Build from the docs/ directory with Sphinx
 sphinx:
   configuration: docs/conf.py
 
-# Explicitly set the version of Python and its requirements
 python:
-  version: 3.8
   install:
     - requirements: docs/requirements.txt