chore(package): update load-grunt-tasks to version 5.1.0

Closes #15

Author: greenkeeper[bot]

package.json

@@ -36,7 +36,7 @@
     "karma-jasmine": "*",
     "karma-junit-reporter": "^1.2.0",
     "karma-phantomjs-launcher": "*",
-    "load-grunt-tasks": "^3.2.0",
+    "load-grunt-tasks": "^5.1.0",
     "time-grunt": "^1.2.1"
   },
   "engines": {