Bump express from 4.18.2 to 4.18.3 in /checkout-example-advanced (#362)

Bumps [express](https://github.com/expressjs/express) from 4.18.2 to 4.18.3.
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/master/History.md)
- [Commits](expressjs/express@4.18.2...4.18.3)

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

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>