Update RTD config

.readthedocs.yml

@@ -1,12 +1,20 @@
 version: 2
 
 build:
-  image: latest
+  os: ubuntu-22.04
+  tools:
+    python: "3.12"
+
+sphinx:
+  configuration: docs/conf.py
+  fail_on_warning: true
 
 python:
-  version: 3.8
   install:
     - method: pip
       path: .
       extra_requirements:
         - docs
+
+# Don't build any extra formats
+formats: []