Add v1.6.0-beta.4 release
Add v1.6.0-beta.4 release

kubernetes/minikube,warmchang/minikube,kubernetes/minikube,skipjaq/minikube,dlorenc/minikube,dongsupark/minikube,aaron-prindle/minikube,r2d4/minikube,dongsupark/minikube,r2d4/minikube,warmchang/minikube,mikegrass/minikube,skipjaq/minikube,abbytiz/minikube,warmchang/minikube,dongsupark/minikube,kubernetes/minikube,dims/minikube,dims/minikube,cu12/minikube,warmchang/minikube,dlorenc/minikube,dlorenc/minikube,endocode/minikube,dlorenc/minikube,abbytiz/minikube,cu12/minikube,aaron-prindle/minikube,cu12/minikube,warmchang/minikube,dalehamel/minikube,dlorenc/minikube,mikegrass/minikube,endocode/minikube,skipjaq/minikube,abbytiz/minikube,kubernetes/minikube,mikegrass/minikube,kubernetes/minikube,kubernetes/minikube,r2d4/minikube,dims/minikube,dalehamel/minikube,warmchang/minikube,dalehamel/minikube,dlorenc/minikube,warmchang/minikube,kubernetes/minikube,aaron-prindle/minikube,endocode/minikube,dlorenc/minikube,dlorenc/minikube