chore(deps-dev): bump fastify from 4.19.2 to 4.21.0 (#932)

Bumps [fastify](https://github.com/fastify/fastify) from 4.19.2 to 4.21.0.
- [Release notes](https://github.com/fastify/fastify/releases)
- [Commits](fastify/fastify@v4.19.2...v4.21.0)

---
updated-dependencies:
- dependency-name: fastify
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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