fix(deps): update dependency fastify to v5.8.1 [security]

Author: renovate[bot]

package.json

@@ -28,7 +28,7 @@
     "diff": "7.0.0",
     "discord.js": "14.19.3",
     "dotenv": "16.6.1",
-    "fastify": "5.7.3",
+    "fastify": "5.8.1",
     "graphql-request": "7.3.5",
     "highlight.js": "11.11.1",
     "mongodb": "6.21.0",