Fix GitLab Runner

Since the TUHH updated the GitLab, the GitLab runner registry does not work for our pipelines anymore. When triggering a pipeline, the access to our Docker image is denied and the pipeline fails immediately (e.g. https://collaborating.tuhh.de/ckv0173/Scilab-RL/-/jobs/955879). Can you please look into that @czs4581 ?

The goal is not that the pipeline succeeds (it might fail because of my changes) but that it does not fail immediately because of the registry.