fix(deps): update dependency @nestjs/schedule to v6

Author: renovate[bot]

backend/package.json

@@ -37,7 +37,7 @@
     "@nestjs/common": "11.1.0",
     "@nestjs/core": "11.1.0",
     "@nestjs/platform-fastify": "11.1.0",
-    "@nestjs/schedule": "5.0.1",
+    "@nestjs/schedule": "6.0.0",
     "@nestjs/swagger": "7.4.2",
     "axios": "1.9.0",
     "class-transformer": "0.5.1",