chore(deps): update dependency supertest to v6 (#308)

Author: renovate-bot

scheduler/package.json

@@ -21,6 +21,6 @@
   "devDependencies": {
     "chai": "^4.2.0",
     "mocha": "^8.0.0",
-    "supertest": "^4.0.0"
+    "supertest": "^6.0.0"
   }
 }