Update incident_sub_status

curl --request PUT \
  --url https://api.rootly.com/v1/incident_sub_statuses/{id} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/vnd.api+json' \
  --data '
{
  "data": {
    "type": "incident_sub_statuses",
    "attributes": {
      "sub_status_id": "<string>",
      "assigned_at": "<string>",
      "assigned_by_user_id": 123
    }
  }
}
'

{
  "data": {
    "id": "70c8af64-68f7-48d6-80fc-100057a9a200",
    "type": "incident_sub_statuses",
    "attributes": {
      "sub_status_id": "d894dcb0-61af-40c4-8899-339d8e906fc4",
      "incident_id": "4fd69a6b-b442-454d-a327-f45630accaa7",
      "assigned_at": "2026-01-16T12:42:12.000-08:00",
      "assigned_by_user_id": 609
    },
    "relationships": {
      "sub_status": {
        "data": {
          "id": "d894dcb0-61af-40c4-8899-339d8e906fc4",
          "type": "sub_statuses"
        }
      },
      "assigned_by_user": {
        "data": {
          "id": "609",
          "type": "users"
        }
      }
    }
  }
}