fix(package): update mongodb to version 3.1.4

Author: greenkeeper[bot]

package.json

@@ -32,7 +32,7 @@
     "lodash": "4.17.5",
     "lru-cache": "4.1.3",
     "mime": "2.3.1",
-    "mongodb": "3.1.3",
+    "mongodb": "3.1.4",
     "parse": "2.0.1",
     "pg-promise": "8.4.6",
     "redis": "2.8.0",