chore(deps): update dev dependency fastify to v5.6.0 (#538)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package.json

@@ -44,7 +44,7 @@
     "@eik/semantic-release-config": "1.0.8",
     "@eik/typescript-config": "1.0.0",
     "eslint": "9.35.0",
-    "fastify": "5.5.0",
+    "fastify": "5.6.0",
     "npm-run-all2": "8.0.4",
     "postcss": "8.5.6",
     "prettier": "3.6.2",