Fix Regular Expression Denial of Service (ReDoS)

https://snyk.io/vuln/npm:ms:20170412

Author: hubdotcom

package.json

@@ -18,7 +18,7 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "ms": "1.0.0"
+    "ms": "2.0.0"
   },
   "devDependencies": {
     "browserify": "9.0.3",