Bump jsonwebtoken from 8.5.1 to 9.0.0 in /backend

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
...

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Author: dependabot[bot]

backend/package-lock.json

@@ -19,7 +19,7 @@
     "express": "^4.17.1",
     "https": "^1.0.0",
     "js-yaml": "^3.14.0",
-    "jsonwebtoken": "^8.5.1",
+    "jsonwebtoken": "^9.0.0",
     "knex": "^0.21.14",
     "openapi": "^1.0.0",
     "openapi-lint": "0.0.1",