Add message to hack/release_notes.sh to tell maintainers to update contributions.
Add message to hack/release_notes.sh to tell maintainers to update contributions.

kubernetes/minikube,kubernetes/minikube,kubernetes/minikube,warmchang/minikube,warmchang/minikube,kubernetes/minikube,warmchang/minikube,kubernetes/minikube,warmchang/minikube,warmchang/minikube,kubernetes/minikube,kubernetes/minikube,warmchang/minikube,warmchang/minikube