chore(deps-dev): Bump fastify from 4.20.0 to 4.21.0 (#798)

Bumps [fastify](https://github.com/fastify/fastify) from 4.20.0 to 4.21.0.
- [Release notes](https://github.com/fastify/fastify/releases)
- [Commits](fastify/fastify@v4.20.0...v4.21.0)

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

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