fix(package): update mongodb to version 3.1.0

Author: greenkeeper[bot]

package.json

@@ -32,7 +32,7 @@
     "lodash": "4.17.5",
     "lru-cache": "4.1.2",
     "mime": "2.3.1",
-    "mongodb": "3.0.7",
+    "mongodb": "3.1.0",
     "multer": "1.3.0",
     "parse": "1.11.1",
     "pg-promise": "8.4.0",