Retrieves a heartbeat

curl --request GET \
  --url https://api.rootly.com/v1/heartbeats/{id} \
  --header 'Authorization: Bearer <token>'

{
  "data": {
    "id": "961a5fbd-2204-4eee-9471-e4cfcde0c27d",
    "type": "heartbeats",
    "attributes": {
      "slug": "autem-et-sit-ipsam",
      "name": "Autem et sit ipsam.",
      "description": "Asperiores repudiandae rerum earum.",
      "alert_summary": "API is down",
      "alert_description": null,
      "alert_urgency_id": "c2c307ea-39ae-4c4e-90af-d50320c83395",
      "interval": 4,
      "interval_unit": "hours",
      "notification_target_id": "209",
      "notification_target_type": "User",
      "ping_url": "http://localhost:3001/v1/heartbeats/961a5fbd-2204-4eee-9471-e4cfcde0c27d/ping",
      "secret": "heartbeat_386e35ebdfbd325fc5575cdd8c3eddb5feeac522298b65ec807f96c77d6d110c",
      "email_address": "heartbeat-7cb09637e9c6b68b222b8991ec8e535a@test.email.rootly.com",
      "last_pinged_at": null,
      "expires_at": null,
      "enabled": false,
      "status": "waiting",
      "updated_at": "2025-10-20T08:30:03.543-07:00",
      "created_at": "2025-10-20T08:30:03.543-07:00"
    }
  }
}