Bump mongoose from 5.4.18 to 5.7.5

Bumps [mongoose](https://github.com/Automattic/mongoose) from 5.4.18 to 5.7.5.
- [Release notes](https://github.com/Automattic/mongoose/releases)
- [Changelog](https://github.com/Automattic/mongoose/blob/master/History.md)
- [Commits](https://github.com/Automattic/mongoose/compare/5.4.18...5.7.5)

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

package.json

@@ -48,7 +48,7 @@
     "mongodb": "^2.2.36",
     "mongojs": "^2.6.0",
     "mongojs-paginate": "^1.2.0",
-    "mongoose": "^5.4.18",
+    "mongoose": "^5.7.5",
     "mpromise": "^0.5.5",
     "nodemailer": "^4.7.0",
     "passport": "^0.4.0",