Bump mongoose from 7.5.2 to 8.0.1 in /backend

Bumps [mongoose](https://github.com/Automattic/mongoose) from 7.5.2 to 8.0.1.
- [Release notes](https://github.com/Automattic/mongoose/releases)
- [Changelog](https://github.com/Automattic/mongoose/blob/master/CHANGELOG.md)
- [Commits](Automattic/mongoose@7.5.2...8.0.1)

---
updated-dependencies:
- dependency-name: mongoose
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

backend/package-lock.json

@@ -28,7 +28,7 @@
     "dotenv": "^16.3.1",
     "express": "^4.18.2",
     "jsonwebtoken": "^9.0.2",
-    "mongoose": "^7.5.2",
+    "mongoose": "^8.0.1",
     "morgan": "^1.10.0"
   },
   "devDependencies": {