Merge pull request #78798 from distortedsignal/default-use-mod

Force using Go Modules in README.md

staging/src/k8s.io/sample-cli-plugin/README.md

@@ -31,7 +31,7 @@ This is an example of how to build a kubectl plugin using the same set of tools
 
 ```sh
 # assumes you have a working KUBECONFIG
-$ go build cmd/kubectl-ns.go
+$ GO111MODULE="on" go build cmd/kubectl-ns.go
 # place the built binary somewhere in your PATH
 $ cp ./kubectl-ns /usr/local/bin