fix: adapt readthedocs job for poetry

.readthedocs.yaml

@@ -13,14 +13,10 @@ build:
   jobs:
     post_create_environment:
       # Install poetry
-      # https://python-poetry.org/docs/#installing-manually
+      # https://github.com/readthedocs/readthedocs.org/issues/4912#issuecomment-1992286540
       - 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
+      - VIRTUAL_ENV=$READTHEDOCS_VIRTUALENV_PATH poetry install
       # Switch to CPU-only PyTorch
       - pip install torch --index-url https://download.pytorch.org/whl/cpu