Update dependency fastify-plugin to v6

Author: renovate[bot]

package.json

@@ -30,7 +30,7 @@
     "@fastify/static": "^8.2.0",
     "@platformatic/python-node": "^2.0.0",
     "@platformatic/service": "^3.0.0",
-    "fastify-plugin": "^5.0.0"
+    "fastify-plugin": "^6.0.0"
   },
   "devDependencies": {
     "cleaner-spec-reporter": "^1.0.0",