rtd: upgrade to Python 3.11 & ubuntu 22.04

Author: mr-c

.readthedocs.yml

@@ -12,9 +12,13 @@ sphinx:
 # Optionally build your docs in additional formats such as PDF and ePub
 formats: all
 
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.11"
+
 # Optionally set the version of Python and requirements required to build your docs
 python:
-  version: 3.7
   install:
    - method: pip
      path: .