ci: fix docs pipeline

.readthedocs.yaml

@@ -5,7 +5,7 @@ build:
   tools:
     python: "3.12"
   jobs:
+    post_create_environment:
+      - python -m pip install poetry
     post_install:
-      - pip install -U poetry
-      - poetry config virtualenvs.create false
-      - poetry install -E docs
+      - VIRTUAL_ENV=$READTHEDOCS_VIRTUALENV_PATH poetry install -E docs