Update .readthedocs.yaml

.readthedocs.yaml

@@ -1,15 +1,20 @@
 # .readthedocs.yaml
 # Read the Docs configuration file
-# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+# See https://docs.readthedocs.io/en/stable/config-file for details
 
 # Required
 version: 2
 
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.9"
+
 # Build documentation in the docs/ directory with Sphinx
 sphinx:
    configuration: docs/conf.py
 
 # Optionally declare the Python requirements required to build your docs
 python:
    install:
-   - requirements: docs/requirements.txt
+   - requirements: docs/requirements.txt