Added grader_id to aicrowd.json

aicrowd.json

 {
-  "challenge_id": "airborne-detection-challenge",
+  "challenge_id": "evaluations-api-airborne",
+  "grader_id": "evaluations-api-airborne",
   "authors": ["aicrowd-bot"],
   "tags": "change-me",
   "description": "Random prediction model for Airborne challenge",