rtd - add poetry to conf

.readthedocs.yaml

@@ -5,3 +5,12 @@ build:
     os: ubuntu-20.04
     tools:
         python: "3.12"
+    jobs:
+        post_create_environment:
+            # Install poetry
+            # https://python-poetry.org/docs/#installing-manually
+            - python -m pip install poetry
+        post_install:
+            # Install dependencies with 'docs' dependency group
+            # https://python-poetry.org/docs/managing-dependencies/#dependency-groups
+            - VIRTUAL_ENV=$READTHEDOCS_VIRTUALENV_PATH poetry install --with docs