- use more current debian repo

gitlab-ci/Dockerfile

@@ -9,7 +9,7 @@ ENV EXLIBRIS_PATH=/exlibris
 RUN apt-get update; \
     apt-get install -y --no-install-recommends gnupg wget; \
     wget -O - http://sdvdebianrepo.slub-dresden.de/deb-repository/pub.gpg.key | apt-key add - ; \
-    echo "deb http://sdvdebianrepo.slub-dresden.de/deb-repository bullseye main" > /etc/apt/sources.list.d/slub.list;
+    echo "deb http://sdvdebianrepo.slub-dresden.de/deb-repository bookworm main" > /etc/apt/sources.list.d/slub.list;
 
 RUN apt-get update; \
     apt-get -y upgrade; \