Update Python version for readthedocs build [no ci]

Author: andreped

docs/requirements.txt

@@ -1,3 +1,2 @@
 sphinx==5.3.0
-sphinx-rtd-theme
-urllib3==1.26.15
+sphinx-rtd-theme

readthedocs.yml

@@ -1,5 +1,15 @@
+# .readthedocs.yaml
+
+# required
 version: 2
 
+# set the version of Python and other tools you might need
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.11"
+
+# build documentation in the docs/ directory with Sphinx
 sphinx:
   builder: html
   configuration: docs/conf.py
@@ -8,8 +18,8 @@ sphinx:
 build:
   image: latest
 
+# declare the Python requirements required to build your docs
 python:
-  version: 3.8
   install:
     - requirements: docs/requirements.txt
     - method: pip