[v9r1] CI: adapt gitlab-ci.yml to Runner v11
Following this intervention, the runner variable has changed a bit: https://cern.service-now.com/service-portal/view-outage.do?n=OTG0044665
Following this intervention, the runner variable has changed a bit: https://cern.service-now.com/service-portal/view-outage.do?n=OTG0044665