build(deps): bump validator and z-schema in /examples/lb4-express (#72)

Bumps [validator](https://github.com/validatorjs/validator.js) and [z-schema](https://github.com/zaggino/z-schema). These dependencies needed to be updated together.

Updates `validator` from 13.1.1 to 13.9.0
- [Release notes](https://github.com/validatorjs/validator.js/releases)
- [Changelog](https://github.com/validatorjs/validator.js/blob/master/CHANGELOG.md)
- [Commits](validatorjs/validator.js@13.1.1...13.9.0)

Updates `z-schema` from 4.2.3 to 4.2.4
- [Release notes](https://github.com/zaggino/z-schema/releases)
- [Commits](zaggino/z-schema@v4.2.3...v4.2.4)

---
updated-dependencies:
- dependency-name: validator
  dependency-type: indirect
- dependency-name: z-schema
  dependency-type: indirect
...

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Author: dependabot[bot]