[ci] get the right path for the docker image

.gitlab-ci.yml

@@ -145,7 +145,7 @@ branded_push:
 
 
 trigger_deb:
-  image: 0xacab.org:4567/leap/docker/buster_amd64:latest
+  image: 0xacab.org:4567/leap/docker/debian:buster_amd64
   stage: trigger
   script:
     - "curl -X POST -F token=$RISEUP_VPN_DEB_TRIGGER_TOKEN -F ref=master https://0xacab.org/api/v4/projects/1916/trigger/pipeline"