Update grunt-concurrent to version 2.3.1 🚀 (#3532)

* chore(package): update grunt-concurrent to version 2.3.1

https://greenkeeper.io/

* update CHANGELOG

CHANGELOG.md

@@ -16,6 +16,7 @@ CHANGELOG
 * @gkatsev reverted back to qunitjs 1.x to unbreak IE8. Added es5-shim to tests ([view](https://github.com/videojs/video.js/pull/3533))
 * @gkatsev updated build system to open es5 folder for bundles and dist folder other users ([view](https://github.com/videojs/video.js/pull/3445))
 * greenkeeper updated uglify ([view](https://github.com/videojs/video.js/pull/3547))
+* greenkeeper updated grunt-concurrent ([view](https://github.com/videojs/video.js/pull/3532))
 
 --------------------
 

package.json

@@ -59,7 +59,7 @@
     "grunt-banner": "^0.4.0",
     "grunt-browserify": "3.5.1",
     "grunt-cli": "~0.1.13",
-    "grunt-concurrent": "^1.0.0",
+    "grunt-concurrent": "^2.3.1",
     "grunt-contrib-clean": "~0.4.0a",
     "grunt-contrib-concat": "^0.5.1",
     "grunt-contrib-connect": "~0.7.1",