Use deb-git-version-gen to create changelog files for snapshots

This will create meaningful (and increasing) version numbers for
building snapshots.

Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>

apertis-package-source-builder/overlay/usr/bin/ci-buildpackage

@@ -60,7 +60,7 @@ esac
 
 if [ -z "$CI_COMMIT_TAG" ]
 then
-    sed '1 {s/.*/'"$pkg ($dversion~) UNRELEASED; urgency=low"'/}' -i debian/changelog
+    deb-git-version-gen  --dch --debug
 fi
 
 rm -rf debian/apertis/gitlab-ci.yml