Bump mongoose from 5.2.8 to 5.7.5

Bumps [mongoose](https://github.com/Automattic/mongoose) from 5.2.8 to 5.7.5.
- [Release notes](https://github.com/Automattic/mongoose/releases)
- [Changelog](https://github.com/Automattic/mongoose/blob/master/History.md)
- [Commits](Automattic/mongoose@5.2.8...5.7.5)

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

Author: dependabot[bot]

package-lock.json

@@ -12,6 +12,6 @@
   "dependencies": {
     "ejs": "^2.6.1",
     "express": "^4.16.3",
-    "mongoose": "^5.2.7"
+    "mongoose": "^5.7.5"
   }
 }