fix kubectl url in sonobuoy

sonobuoy/Makefile

@@ -13,7 +13,7 @@ SUDO = sudo
 endif
 
 SONOBUOY_URL = https://github.com/vmware-tanzu/sonobuoy/releases/download/v$(SONOBUOY_VERSION)/sonobuoy_$(SONOBUOY_VERSION)_linux_amd64.tar.gz
-KUBECTL_URL = https://storage.googleapis.com/kubernetes-release/release/v$(KUBECTL_VERSION)/bin/linux/amd64/kubectl
+KUBECTL_URL = https://dl.k8s.io/v$(K8S_VERSION)/bin/linux/amd64/kubectl
 DOCKER_COMPOSE_URL = https://github.com/docker/compose/releases/download/v$(DOCKER_COMPOSE_VERSION)/docker-compose-Linux-x86_64
 CKECLI = ./bin/ckecli --config=./cke.config
 KUBECONFIG := $(shell pwd)/.kubeconfig