Mirrored a setup on GitHub

See: readthedocs/readthedocs.org#4912 (comment)

Author: jrg94

.readthedocs.yaml

@@ -6,10 +6,9 @@ build:
       python: "3.11"
    jobs:
       post_create_environment:
-         - pip install poetry
-         - poetry config virtualenvs.create false
+         - python -m pip install poetry
       post_install:
-         - poetry install --with docs
+         - VIRTUAL_ENV=$READTHEDOCS_VIRTUALENV_PATH poetry install --with docs
 
 sphinx:
    configuration: docs/conf.py