build(deps): bump fastify from 4.20.0 to 4.21.0

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:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -43,7 +43,7 @@
     "standard": "*"
   },
   "dependencies": {
-    "fastify": "^4.20.0",
+    "fastify": "^4.21.0",
     "fastify-cli": "^5.7.1",
     "@fastify/env": "^4.2.0",
     "@fastify/mongodb": "^7.0.0"