Makefile: push docker images to latest instead of specific revisions
Makefile: push docker images to latest instead of specific revisions

warmchang/minikube,kubernetes/minikube,kubernetes/minikube,warmchang/minikube,dlorenc/minikube,kubernetes/minikube,kubernetes/minikube,kubernetes/minikube,warmchang/minikube,dlorenc/minikube,dalehamel/minikube,warmchang/minikube,kubernetes/minikube,dlorenc/minikube,dlorenc/minikube,dlorenc/minikube,dlorenc/minikube,dlorenc/minikube,dalehamel/minikube,dalehamel/minikube,warmchang/minikube,warmchang/minikube,kubernetes/minikube,warmchang/minikube,dlorenc/minikube