feat: add initial attempt at a template level github action to sync demos on PR updates that target develop

Author: 56kyle

.github/workflows/sync-demos.yml

@@ -0,0 +1,49 @@
+name: sync-demo.yml
+on:
+  pull_request:
+    branches:
+      - develop
+
+env:
+  COOKIECUTTER_ROBUST_PYTHON__DEMOS_CACHE_FOLDER: ${{ github.workspace }}
+  COOKIECUTTER_ROBUST_PYTHON__APP_AUTHOR: ${{ github.repository_owner }}
+  ROBUST_PYTHON_DEMO__APP_AUTHOR: ${{ github.repository_owner }}
+  ROBUST_MATURIN_DEMO__APP_AUTHOR: ${{ github.repository_owner }}
+
+jobs:
+  update-demo:
+    name: Update Demo
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        demo:
+          - { name: "robust-python-demo", session_modifier: "no-rust" }
+          - { name: "robust-maturin-demo", session_modifier: "rust" }
+    steps:
+      - name: Checkout Template
+        uses: actions/checkout@v4
+        with:
+          repository: ${{ github.repository }}
+          path: cookiecutter-robust-python
+          ref: ${{ github.head_ref }}
+
+      - name: Checkout Demo
+        uses: actions/checkout@v4
+        with:
+          repository: "${{ github.repository_owner }}/${{ matrix.demo.name }}"
+          path: ${{ matrix.demo.name }}
+          ref: develop
+
+      - name: Set up uv
+        uses: astral-sh/setup-uv@v6
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Update Demo
+        run: "uvx nox -s 'update-demo(${{ matrix.demo.session_modifier }})'"
+
+