Fix Poetry & ReadTheDocs

Author: ewjoachim

.readthedocs.yml

@@ -13,7 +13,8 @@ build:
   tools:
     python: "3.10"
   jobs:
+    post_create_environment:
+      - pip install poetry
     post_install:
-      - pip install -U poetry
-      - poetry config virtualenvs.create false
-      - poetry install --with docs
+      - VIRTUAL_ENV=$READTHEDOCS_VIRTUALENV_PATH poetry install --with docs
+