ci: add stage where debmagic packages itself

Author: mikonse

.github/workflows/ci.yml

@@ -107,3 +107,22 @@ jobs:
   #       run: uv sync --locked --all-extras --dev
   #     - name: Run Integrationtests
   #       run: uv run pytest tests/integration
+
+  package_ourself:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+      - name: Set up Python
+        uses: actions/setup-python@v6
+        with:
+          python-version: "3.12"
+      - name: Install uv
+        uses: astral-sh/setup-uv@v6
+        with:
+          enable-cache: true
+      - name: Install the project
+        run: uv sync --locked --all-extras --dev
+      - name: Install required apt 
+        run: apt-get install -y devscripts
+      - name: Run Debmagic build on ourself
+        run: uv run debmagic build --driver=none