Depend on new pluginator location.

plugin/tools.go

@@ -0,0 +1,13 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+// +build tools
+
+// This file exists to declare that package
+// plugin explicitly depends on the pluginator
+// tool (via go:generate directives)
+package plugin
+
+import (
+	_ "sigs.k8s.io/kustomize/pluginator"
+)