build(deps): bump path-to-regexp and express in /example/frontend

Bumps [path-to-regexp](https://github.com/pillarjs/path-to-regexp) and [express](https://github.com/expressjs/express). These dependencies needed to be updated together.

Updates `path-to-regexp` from 1.8.0 to 1.9.0
- [Release notes](https://github.com/pillarjs/path-to-regexp/releases)
- [Changelog](https://github.com/pillarjs/path-to-regexp/blob/master/History.md)
- [Commits](pillarjs/path-to-regexp@v1.8.0...v1.9.0)

Updates `express` from 4.17.1 to 4.20.0
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/master/History.md)
- [Commits](expressjs/express@4.17.1...4.20.0)

---
updated-dependencies:
- dependency-name: path-to-regexp
  dependency-type: indirect
- dependency-name: express
  dependency-type: indirect
...

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