Use dl.k8s.io for getting kubectl

scripts/Dockerfile

@@ -6,7 +6,7 @@ RUN  apt-get update && \
      apt-get clean && \
      rm -rf /var/cache/apt/archives/* /var/lib/apt/lists/* && \
      go get -u golang.org/x/lint/golint && \
-     curl -L https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl -o /usr/bin/kubectl && chmod 755 /usr/bin/kubectl && \
+     curl -L https://dl.k8s.io/release/$(curl -sL https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl -o /usr/bin/kubectl && chmod 755 /usr/bin/kubectl && \
      curl -LO https://releases.hashicorp.com/terraform/0.12.20/terraform_0.12.20_linux_amd64.zip && unzip terraform_0.12.20_linux_amd64.zip && \
      mv terraform /usr/bin/terraform && chmod 755 /usr/bin/terraform && rm terraform_0.12.20_linux_amd64.zip 
 VOLUME /go/src/github.com/rancher/terraform-provider-rke