Bump fastify from 5.2.0 to 5.2.1 in /nodejs-fastify-webhook

Bumps [fastify](https://github.com/fastify/fastify) from 5.2.0 to 5.2.1.
- [Release notes](https://github.com/fastify/fastify/releases)
- [Commits](fastify/fastify@v5.2.0...v5.2.1)

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

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