CI: add ci .deb build step

.github/workflows/test-build.yml

@@ -0,0 +1,51 @@
+name: test-build
+on:
+  pull_request:
+  push:
+
+concurrency:
+  group: "${{ github.ref }}"
+  cancel-in-progress: true
+jobs:
+  build-debian:
+    strategy:
+      # Keep other matrix jobs running, even if one fails.
+      fail-fast: false
+      matrix:
+        host_release:
+          - unstable
+
+    # We want a working shell, qemu, python and docker. Specific version should not matter (much).
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: "Build .deb"
+        run: |
+          sudo apt-get update
+          sudo apt-get install -qq -y --no-install-recommends build-essential devscripts equivs
+          SOURCEDIR="$PWD"
+          cd /tmp
+          mk-build-deps -ir -t 'apt-get -o Debug::pkgProblemResolver=yes --no-install-recommends -y' "$SOURCEDIR"/debian/control
+          dpkg-source -b "$SOURCEDIR"
+          dpkg-source -x ./*.dsc builddir
+          cd builddir
+          OLD_VERSION=$(dpkg-parsechangelog -SVersion)
+          SOURCE=$(dpkg-parsechangelog -SSource)
+          cat > debian/changelog <<EOT
+          ${SOURCE} (${OLD_VERSION}+autobuild${BUILD_NUMBER}) UNRELEASED; urgency=medium
+          
+            * Automated Build
+          
+           -- Automated Build <builder@localhost>  $(date -R)
+          EOT
+          dpkg-buildpackage -b --no-sign
+          mv ../*deb "$SOURCEDIR"/
+      - name: Archive built .deb
+        uses: actions/upload-artifact@v4
+        with:
+          name: deb-${{matrix.host_release}}
+          if-no-files-found: error
+          path: |
+            *.deb