ci: Add zypp backend to CI (debian)

For building and installing purposes, 'libzypp' / 'libzypp-dev'
packages provided by debian are sufficient. So, we not build and test
'zypp' backend directly in Debian CI after 'apt' backend test.

.github/workflows/build-test.yml

@@ -28,4 +28,5 @@ jobs:
       - name: Build & Test [APT]
         run: podman run -t -v `pwd`:/build packagekit-${{ matrix.distro }}
              ./tests/ci/build-and-test.sh -Dpackaging_backend=apt
+             ./tests/ci/build-and-test.sh -Dpackaging_backend=zypp
         if: ${{ matrix.distro == 'debian' }}

tests/ci/Dockerfile-debian

@@ -13,6 +13,9 @@ RUN apt-get install -yq build-essential
 RUN apt-get build-dep -yq packagekit
 RUN apt-get install -yq meson appstream
 
+# install PackageKit dependencies for zypp backend
+RUN apt-get install -yq libzypp-dev
+
 # finish
 RUN mkdir /build
 WORKDIR /build