ci-package-builder: Use the right package name on pull-updates

In some cases the GitLab project name and the package name do not match, for instance gtk+3.0 being packaged at pkg/gtk-3.0>.

Now that with the external CI config we can run the pipeline on the debian/* branches and access the data there, we can find the correct package name by looking at debian/changelog.

ci-package-builder.yml

@@ -91,10 +91,11 @@ pull-updates:
   only:
     - /^debian\//
   script:
+    - PACKAGE=$(dpkg-parsechangelog -SSource || echo "$CI_PROJECT_NAME")
     - >
       apertis-pkg-pull-updates
-      --package=${CI_PROJECT_NAME}
-      --upstream=${UPSTREAM_RELEASE}
+      --package=${PACKAGE}
+      --upstream=${UPSTREAM_RELEASE##*/}
       --mirror=${DEBIAN_MIRROR}
     - |
         if [ -f .git/refs/heads/pristine-lfs ] ; then