Publish KubeCF helm chart

[fargozhu]

Summary

To have KubeCF helm chart available through it's on repo on every publish release.

Intended Outcome

$ helm repo add kubecf https://cloudfoundry-incubator.github.io/kubecf-helm/
$ helm repo update
$ helm show readme kubecf/kubecf
$ helm install kubecf kubecf/kubecf

[fargozhu]

fixed by #78