build(deps): bump express from 4.21.2 to 4.22.1 in /examples/github-app

Bumps [express](https://github.com/expressjs/express) from 4.21.2 to 4.22.1.
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/v4.22.1/History.md)
- [Commits](expressjs/express@4.21.2...v4.22.1)

---
updated-dependencies:
- dependency-name: express
  dependency-version: 4.22.1
  dependency-type: indirect
...

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

Author: dependabot[bot]