[MAINT] update RTD config

Author: Remi-Gau

.readthedocs.yml

@@ -5,6 +5,11 @@
 
 version: 2
 
+build:
+  os: ubuntu-22.04
+  tools:
+    python: '3.12'
+
 sphinx:
   configuration: docs/source/conf.py
   builder: html
@@ -14,6 +19,5 @@ formats:
 - pdf
 
 python:
-  version: '3.8'
   install:
   - requirements: requirements.txt