Feature/block merge master outofdate

Today an incident made me realize that we don't block merge if the feature branch doesn't have master up to date.

Given the nature of our pipelines is key that we do that, to avoid that the entire yaml gets invalid.

What can happen is that a job relies on a private job/reference. If that reference is delete in master but still present in the local master, than the MR pipelines will not pick up on that and the test will be successful. Git will not flag this as a potential merge conflict either, and the MR can be merged, giving only once merged the issue.

In the current git version we can easily merge a feature branch with master out of date as long as there are no MR conflicts with master because git will only evaluate the new diff. This MR will enforce the developer to keep master local up to date with origin and avoid this issues in the future