Update ejs dependency vulnerability

Author: keitharm

package.json

@@ -13,7 +13,7 @@
     "cookie-parser": "~1.3.5",
     "cors": "^2.7.1",
     "debug": "~2.2.0",
-    "ejs": "~2.3.3",
+    "ejs": "^2.5.7",
     "express": "~4.13.1",
     "filesize": "^3.2.1",
     "format-number": "^2.0.1",