gitlab/gitlab-ci.yml: Fail on lintian errors.

4 jobs for master in 7 minutes and 55 seconds
Status Job ID Name Coverage
  Test
passed #192269
buster
buster

00:04:25

passed #192271
centos7
centos7

00:05:11

passed #192268
sid

00:07:52

passed #192270
stretch
stretch

00:04:20