Update the go get to k8s.io/sample-controller
Update the go get to k8s.io/sample-controller

Referring to the issue: https://github.com/kubernetes/sample-controller/issues/20#issuecomment-398716033

Kubernetes-commit: 6d631e32f281949e1b31e65e0cbd203be39a1c6f

kubernetes/sample-controller,kubernetes/sample-controller