chore(package): update lodash to version 4.17.15

Closes #46

Author: greenkeeper[bot]

package.json

@@ -53,7 +53,7 @@
     "gulp-uglifyjs": "0.6.2",
     "gulp-util": "3.0.8",
     "gulp-verb": "0.3.0",
-    "lodash": "4.17.11",
+    "lodash": "4.17.15",
     "verb": "0.8.10"
   }
 }