GitLab Helm chart is ready for Kubernetes 1.16 apiversion deprecations

Summary

Kubernetes 1.16 no longer will be serving extensions/* and apps/beta* API versions, all resources should stop using them

Relevant links

• https://kubernetes.io/blog/2019/07/18/api-deprecations-in-1-16/
• https://kubernetes.io/blog/2019/09/18/kubernetes-1-16-release-announcement/