chore(deps): bump express from 4.19.1 to 4.21.2 in /functions

Bumps [express](https://github.com/expressjs/express) from 4.19.1 to 4.21.2.
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/4.21.2/History.md)
- [Commits](expressjs/express@4.19.1...4.21.2)

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

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