ci: change post_create_environment on readthedocs.yaml

.readthedocs.yaml

@@ -10,8 +10,7 @@ build:
 
   jobs:
     post_create_environment:
-      - pip install poetry
-      - poetry config virtualenvs.create false
+      - pip install --user --requirement < (poetry export --format requirements.txt)
 
     post_install:
       - poetry install --only doc