use carat on assert package

Author: substack

package.json

@@ -21,7 +21,7 @@
   ],
   "dependencies": {
     "JSONStream": "^1.0.3",
-    "assert": "~1.4.0",
+    "assert": "^1.4.0",
     "browser-pack": "^6.0.1",
     "browser-resolve": "^1.11.0",
     "browserify-zlib": "~0.1.2",