Update browserify

Closes GH-2.

Author: greenkeeperio-bot

package.json

@@ -24,7 +24,7 @@
     "unist-util-is": "^2.0.0"
   },
   "devDependencies": {
-    "browserify": "^13.1.1",
+    "browserify": "^14.0.0",
     "esmangle": "^1.0.0",
     "remark": "^6.0.0",
     "remark-cli": "^2.0.0",