Update resources API to stable verson

Overview

Kubernetes v1.16 deprecated API such as extensions/v1beta1 which breaks Helm chart installation for GitLab Runner

Fixes #80 (closed)

How to upgrade

When running the suggested upgrade as the suggested docs you might see errors such as:

Error: Deployment.apps "mothy-moose-gitlab-runner" is invalid: spec.selector: Invalid value: v1.LabelSelector{MatchLabels:map[string]string{"app":"mothy-moose-gitlab-runner", "release":"mothy-moose"}, MatchExpressions:[]v1.LabelSelectorRequirement(nil)}: field is immutable

This is because we are adding the selectors which are required for apps/v1, this can be simply fixed by passing the --force flag for example:

helm upgrade --force --namespace <NAMESPACE> -f <CONFIG_VALUES_FILE> <RELEASE-NAME> gitlab/gitlab-runner