Update .readthedocs.yml

Apparently the 'build' section is required now, builds have been failing for a while because it was missing

.readthedocs.yml

@@ -9,6 +9,12 @@ version: 2
 #sphinx:
 #  configuration: docs/conf.py
 
+# Set the version of Python and other tools you might need
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.12"
+
 # Build documentation with MkDocs
 mkdocs:
   configuration: docs/mkdocs.yml
@@ -19,6 +25,6 @@ mkdocs:
 
 # Optionally set the version of Python and requirements required to build your docs
 python:
-  version: 3.7
+  version: 3.12
   install:
     - requirements: docs/requirements.txt