Update async

package.json

@@ -18,7 +18,7 @@
     "npm": "1.3.x"
   },
   "dependencies": {
-    "async": "=0.1.18",
+    "async": "~0.9.0",
     "aws-sdk": "~2.0.0-rc.19",
     "bower": "~1.3.9",
     "cli": "~0.6.4",