Bump mongodb from 2.2.31 to 3.1.13

Bumps [mongodb](https://github.com/mongodb/node-mongodb-native) from 2.2.31 to 3.1.13.
- [Release notes](https://github.com/mongodb/node-mongodb-native/releases)
- [Changelog](https://github.com/mongodb/node-mongodb-native/blob/master/CHANGES_3.0.0.md)
- [Commits](mongodb/node-mongodb-native@v2.2.31...v3.1.13)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package-lock.json

@@ -47,7 +47,7 @@
     "express": "^4.15.2",
     "fs-extra": "^3.0.1",
     "lodash": "^4.14.1",
-    "mongodb": "^2.2.31",
+    "mongodb": "^3.1.13",
     "node-zip": "^1.1.1",
     "reflect-metadata": "^0.1.10",
     "request": "^2.81.0",