MAINT: use Python 3.11 on readthedocs

(also cleanup the config file indentation)

Author: gdementen

readthedocs.yml

@@ -9,26 +9,26 @@ version: 2
 build:
   os: ubuntu-22.04
   tools:
-    python: "3.10"
+    python: "3.11"
 
 # Build documentation in the doc/ directory with Sphinx
 sphinx:
-    configuration: doc/source/conf.py
+  configuration: doc/source/conf.py
 
 # Optionally build your docs in additional formats such as PDF and ePub
 formats:
-    - pdf
+  - pdf
 
 # we do not use conda anymore because it consumes too much memory and thus crashes our builds
 # see:
 # - https://docs.readthedocs.io/en/stable/guides/build-using-too-many-resources.html#use-pip-when-possible
 # - https://github.com/readthedocs/readthedocs.org/issues/6692
 #conda:
-#    environment: doc/environment.yml
+#  environment: doc/environment.yml
 
 # Optionally declare the Python requirements required to build your docs
 python:
-    install:
-        - requirements: doc/requirements.txt
-        - method: pip
-          path: .
+  install:
+    - requirements: doc/requirements.txt
+    - method: pip
+      path: .