chore(package): update browserify to version 15.2.0

Closes #139

Author: greenkeeper[bot]

package.json

@@ -32,7 +32,7 @@
   },
   "homepage": "https://github.com/ds82/angular-contextmenu",
   "devDependencies": {
-    "browserify": "14.3.0",
+    "browserify": "15.2.0",
     "derequire": "2.0.6",
     "jasmine-core": "2.6.1",
     "jquery": "3.2.1",