Bump jsonwebtoken and notifications-node-client

Bumps [jsonwebtoken](https://github.com/auth0/node-jsonwebtoken) to 9.0.0 and updates ancestor dependency [notifications-node-client](https://github.com/alphagov/notifications-node-client). These dependencies need to be updated together.


Updates `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)

Updates `notifications-node-client` from 5.1.0 to 6.0.0
- [Release notes](https://github.com/alphagov/notifications-node-client/releases)
- [Changelog](https://github.com/alphagov/notifications-node-client/blob/main/CHANGELOG.md)
- [Commits](alphagov/notifications-node-client@5.1.0...6.0.0)

---
updated-dependencies:
- dependency-name: jsonwebtoken
  dependency-type: indirect
- dependency-name: notifications-node-client
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

package.json

@@ -12,7 +12,7 @@
     "@react-google-maps/api": "^2.13.1",
     "@sendgrid/mail": "^7.1.1",
     "isomorphic-unfetch": "^3.0.0",
-    "notifications-node-client": "^5.1.0",
+    "notifications-node-client": "^6.0.0",
     "npm-run-all": "^4.1.5",
     "query-string": "^6.11.1",
     "react": "^16.13.1",