fix readthedocs config (#2468)

* fix readthedocs config

* fix config

* add missing import

.readthedocs.yaml

@@ -7,12 +7,16 @@ version: 2
 
 # Set the version of Python and other tools you might need
 build:
-  image: latest
+  os: ubuntu-22.04
+  tools:
+    python: "3.10"
   apt_packages:
       - libxmlsec1-dev
 
 python:
-  version: "3.8"
+  install:
+    - requirements: docs/requirements.txt
+    - requirements: requirements.txt
 
 # Build documentation in the docs/ directory with Sphinx
 sphinx:
@@ -21,9 +25,3 @@ sphinx:
 # If using Sphinx, optionally build your docs in additional formats such as PDF
 # formats:
 #    - pdf
-
-# Optionally declare the Python requirements required to build your docs
-python:
-   install:
-   - requirements: docs/requirements.txt
-   - requirements: requirements.txt