Bump jsonwebtoken from 8.5.1 to 9.0.0 in /user-service

Bumps [jsonwebtoken](https://github.com/auth0/node-jsonwebtoken) from 8.5.1 to 9.0.0.
- [Release notes](https://github.com/auth0/node-jsonwebtoken/releases)
- [Changelog](https://github.com/auth0/node-jsonwebtoken/blob/master/CHANGELOG.md)
- [Commits](auth0/node-jsonwebtoken@v8.5.1...v9.0.0)

---
updated-dependencies:
- dependency-name: jsonwebtoken
  dependency-type: direct:production
...

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

user-service/package.json

@@ -23,7 +23,7 @@
     "cors": "^2.8.5",
     "email-validator": "^2.0.4",
     "express": "^4.16.4",
-    "jsonwebtoken": "^8.5.1",
+    "jsonwebtoken": "^9.0.0",
     "pg": "^7.9.0",
     "reflect-metadata": "^0.1.13",
     "sequelize": "^5.15.1",