Bump async and mongoose

Removes [async](https://github.com/caolan/async). It's no longer used after updating ancestor dependency [mongoose](https://github.com/Automattic/mongoose). These dependencies need to be updated together.


Removes `async`

Updates `mongoose` from 5.4.12 to 5.13.22
- [Release notes](https://github.com/Automattic/mongoose/releases)
- [Changelog](https://github.com/Automattic/mongoose/blob/5.13.22/History.md)
- [Commits](Automattic/mongoose@5.4.12...5.13.22)

---
updated-dependencies:
- dependency-name: async
  dependency-type: indirect
- dependency-name: mongoose
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package-lock.json

@@ -27,7 +27,7 @@
     "compression": "^1.7.3",
     "cors": "^2.8.5",
     "express": "^4.16.4",
-    "mongoose": "^5.4.12",
+    "mongoose": "^5.13.22",
     "nodemon": "^1.18.10",
     "passport": "^0.4.0",
     "passport-jwt": "^4.0.1",