updating readme to note dropping support of older versions of node

README.md

@@ -11,6 +11,11 @@ I no longer use Gulp and therefore I'm not able to maintain this plugin as well
 [![Build Status](https://travis-ci.org/jackfranklin/gulp-load-plugins.svg?branch=master)](https://travis-ci.org/jackfranklin/gulp-load-plugins)
 
 
+## Node Version Requirements
+
+Due to the native support of ES2015 syntax in newer versions of Node, this plugin requires at least Node v6. If you need to maintain support for older versions of Node, version 1.6.0 of this plugin is the last release that will support Node versions less than 6.
+
+
 ## Install
 
 ```sh