chore: add poetry install to docs

.github/workflows/documentation.yml

@@ -13,7 +13,8 @@ jobs:
       - uses: actions/setup-python@v5
       - name: Install dependencies
         run: |
-          pip install sphinx sphinx_rtd_theme myst_parser
+          pip install poetry
+          poetry install
       - name: Sphinx build
         run: |
           sphinx-build docs _build