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": "87252d21-dbd6-48a3-988f-b7d2d646b6bc",
    "type": "incident_sub_statuses",
    "attributes": {
      "sub_status_id": "c31e325b-9126-40ab-a99e-14b4dd246da5",
      "incident_id": "0129bf9b-4508-4d85-9ea3-0a4cca1c5a1b",
      "assigned_at": "2025-09-16T17:15:30.000-07:00",
      "assigned_by_user_id": 313
    },
    "relationships": {
      "sub_status": {
        "data": {
          "id": "c31e325b-9126-40ab-a99e-14b4dd246da5",
          "type": "sub_statuses"
        }
      },
      "assigned_by_user": {
        "data": {
          "id": "313",
          "type": "users"
        }
      }
    }
  }
}