Try to fix RTD config

.readthedocs.yaml

@@ -4,15 +4,19 @@
 # Required
 version: 2
 
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.9"
+
 # Build documentation in the doc/ directory with Sphinx
 sphinx:
    configuration: doc/conf.py
 
 # Additional formats for download
 formats: all
 
-# Optionally set the version of Python and requirements required to build your docs
+# Requirements required to build your docs
 python:
-   version: 3.7
    install:
    - requirements: requirements-docs.txt