docs: fix the RTD build (#5267)

Bump up the Python version to 3.11, as Sphinx 8.2.3 we pin requires
that. This also aligns the RTD configuration with what our Testing
workflow uses.

Fixes #5123.

Signed-off-by: Alex T. <[email protected]>
Co-authored-by: Sanskar Sharma <[email protected]>

Author: alex-ter

.readthedocs.yml

@@ -9,7 +9,7 @@ version: 2
 build:
   os: ubuntu-22.04
   tools:
-    python: "3.10"
+    python: "3.11"
 
 # Build documentation in the docs/ directory with Sphinx
 sphinx: