ci(readthedocs): resolve poetry install errors

.readthedocs.yml

@@ -6,6 +6,7 @@ sphinx:
   fail_on_warning: false
   builder: html
 
+# https://docs.readthedocs.io/en/stable/build-customization.html#install-dependencies-with-poetry
 build:
   os: ubuntu-22.04
   tools:
@@ -15,9 +16,7 @@ build:
       # Install poetry
       # https://python-poetry.org/docs/#installing-manually
       - pip install poetry
-      # Tell poetry to not use a virtual environment
-      - poetry config virtualenvs.create false
     post_install:
       # Install dependencies with 'docs' dependency group
       # https://python-poetry.org/docs/managing-dependencies/#dependency-groups
-      - poetry install --with docs
+      - VIRTUAL_ENV=$READTHEDOCS_VIRTUALENV_PATH poetry install --with docs