.github/workflows/pages.yml: parse the schema

Try to install Python dependencies with Poetry and then parse the
schema using ./util/generate-hugo-content.py. I'm not sure if we
need to use `poetry run ...` instead.

.github/workflows/pages.yml

@@ -15,8 +15,11 @@ jobs:
           python-version: 3.9
       - name: Install Poetry
         uses: abatilo/actions-poetry@v2.1.4
-      - name: Poetry version
-        run: poetry --version
+      - name: Install Python dependencies
+        run: poetry install
+      - name: Generate Hugo content
+        run: |
+          ./util/generate-hugo-content.py -i data/schema-fields.csv --clean -d
   pages:
     runs-on: ubuntu-latest
     if: ${{ github.ref_name == 'main' }}