build(deps): bump express-rate-limit from 7.3.1 to 7.4.0 in /backend (#41)

Bumps [express-rate-limit](https://github.com/express-rate-limit/express-rate-limit) from 7.3.1 to 7.4.0.
- [Release notes](https://github.com/express-rate-limit/express-rate-limit/releases)
- [Commits](https://github.com/express-rate-limit/express-rate-limit/compare/v7.3.1...v7.4.0)

---
updated-dependencies:
- dependency-name: express-rate-limit
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

backend/package.json

@@ -15,7 +15,7 @@
     "bcrypt": "^5.1.1",
     "cors": "^2.8.5",
     "express": "^4.21.0",
-    "express-rate-limit": "^7.3.1",
+    "express-rate-limit": "^7.4.0",
     "jsonwebtoken": "^9.0.2",
     "multer": "^1.4.5-lts.1",
     "sequelize": "^6.37.3",