Upgrade GitLab Runner to chart version 0.50.1 and app version 15.9.1

No problems deploying to K3s cluster via Helm Chart and Flux V2 reconciliation in a GitOps approach.
v15.9.0 (2023-02-19)
Helm Chart 0.50.0
v15.9.1 (2023-02-20))
Helm Chart 0.50.1