Docs: Install project on RTD

.readthedocs.yaml

@@ -27,9 +27,9 @@ sphinx:
 #    - pdf
 #    - epub
 
-# Optional but recommended, declare the Python requirements required
-# to build your documentation
-# See https://docs.readthedocs.io/en/stable/guides/reproducible-builds.html
-# python:
-#    install:
-#    - requirements: docs/requirements.txt
+python:
+  install:
+    - method: pip
+      path: .
+      extra_requirements:
+        - docs