Update schedule rotation user

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

{
  "data": {
    "id": "e3b6c77c-7cc2-4fd2-a074-3fe12ae4e835",
    "type": "schedule_rotation_users",
    "attributes": {
      "schedule_rotation_id": "2d2012cf-0ae6-4557-9d76-384b6076002a",
      "user_id": 838,
      "position": 2,
      "created_at": "2026-01-09T17:15:56.586-08:00",
      "updated_at": "2026-01-09T17:15:56.592-08:00"
    }
  }
}