fix [.readthedocs.yml] - increase python version

Fixes urllib3 v2.0 not supporting versions <1.1.1 of openSSL. See readthedocs/readthedocs.org#10290.

.readthedocs.yml

@@ -9,17 +9,13 @@ version: 2
 sphinx:
   configuration: docs/conf.py
 
-# Build documentation with MkDocs
-#mkdocs:
-#  configuration: mkdocs.yml
-
 # Optionally build your docs in additional formats such as PDF and ePub
 formats:
   - htmlzip
 
 # Optionally set the version of Python and requirements required to build your docs
 python:
-  version: 3.8
+  version: 3.10
   install:
     - requirements: docs/requirements.txt