Fix instructions for client staging copy

staging/README.md

-This staging/src/k8s.io/client-go directory is the staging area of the client repo. It contains a versioned client, tools built around the client like the reflector, and all the client dependencies. The content will be periodically published to k8s.io/client-go repo.
-The staged content is copied from the main repo, i.e., k8s.io/kubernetes, with directory rearrangement and necessary rewritings. To sync the content with the latest code in your local k8s.io/kubernetes, you need to run `godep restore` in k8s root directory, then run staging/copy.sh.
-vendor/k8s.io/client-go is a symlink pointing to this staging area, so to use the packages in the staging area, you can import it as "vendor/client-go/<package-name>", as if the client were vendored. The client will be vendored from k8s.io/client-go for real after the test matrix is converted to vendor k8s components.
+This staging/src/k8s.io/client-go directory is the staging area of the client
+repo. It contains a versioned client, tools built around the client like the
+reflector, and all the client dependencies. The content will be periodically
+published to k8s.io/client-go repo.
+
+The staged content is copied from the main repo, i.e., k8s.io/kubernetes, with
+directory rearrangement and necessary rewritings. To sync the content with the
+latest code in your local k8s.io/kubernetes, you need to run `godep restore` in
+k8s root directory, then run hack/update-staging-client-go.sh.
+
+vendor/k8s.io/client-go is a symlink pointing to this staging area, so to use
+the packages in the staging area, you can import it as
+"vendor/client-go/<package-name>", as if the client were vendored. The client
+will be vendored from k8s.io/client-go for real after the test matrix is
+converted to vendor k8s components.