removes k8s.io/kubernetes/pkg/api dependency from the webhook plugin.

cmd/kube-apiserver/app/server.go

@@ -484,6 +484,7 @@ func BuildGenericConfig(s *options.ServerRunOptions, proxyTransport *http.Transp
 		certBytes,
 		keyBytes,
 		kubeClientConfig,
+		api.Scheme,
 		pluginInitializer)
 	if err != nil {
 		return nil, nil, nil, nil, nil, fmt.Errorf("failed to initialize admission: %v", err)