doc: fix RTD build and update config

Author: alvarolopez

.readthedocs.yml

@@ -5,6 +5,16 @@
 # Required
 version: 2
 
+# Set the version of Python and other tools you might need
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.11"
+  jobs:
+    # Do not use shallow clone, as reno will complain
+    post_checkout:
+      - git fetch --unshallow
+
 # Build documentation in the docs/ directory with Sphinx
 sphinx:
   configuration: doc/source/conf.py
@@ -13,10 +23,6 @@ sphinx:
 #mkdocs:
 #  configuration: mkdocs.yml
 
-# Optionally build your docs in additional formats such as PDF
-formats:
-  - pdf
-
 # Optionally set the version of Python and requirements required to build your docs
 python:
   install: