Renovate: Group fastify updates

renovate.json

@@ -7,6 +7,12 @@
     "enabled": true,
     "automerge": true
   },
+  "packageRules": [
+    {
+      "groupName": "fastify",
+      "matchPackageNames": ["fastify"]
+    }
+  ],
   "automerge": true,
   "configMigration": true
 }