What does this MR do?
Adds a release step, that pushes gitlab-runner-helper do docker hub. This is a first step to make prebuilt images available for Kubernetes executor.
Why was this MR needed?
Please read !275 (closed) for a reference.
Are there points in the code the reviewer needs to double check?
Does this MR meet the acceptance criteria?
Added for this feature/bug
All builds are passing
Branch has no merge conflicts with
master(if you do - rebase it please)
What are the relevant issue numbers?
Successor of !275 (closed)