build: use ubuntu-lts-latest in readthedocs build

Author: edx-requirements-bot

.readthedocs.yaml

@@ -11,7 +11,7 @@ sphinx:
 
 # Set the version of python needed to build these docs.
 build:
-  os: "ubuntu-22.04"
+  os: "ubuntu-lts-latest"
   tools:
     python: "3.11"