Fix RTD build: install main package for autodoc imports

Author: stringertheory

.readthedocs.yaml

@@ -8,7 +8,7 @@ build:
     post_install:
       - pip install poetry
       - poetry config virtualenvs.create false
-      - poetry install --only docs
+      - poetry install --only main --only docs
 
 sphinx:
   configuration: docs/conf.py