update RTD yaml

.readthedocs.yaml

@@ -1,13 +1,10 @@
-# https://docs.readthedocs.io/en/stable/config-file/v2.html
 version: 2
 build:
   os: ubuntu-20.04
   tools:
-    python: "3.10"
+    python: "3.11"
 sphinx:
   configuration: docs/conf.py
-  # disable this for more lenient docs builds
-  fail_on_warning: true
 python:
   install:
     - method: pip