Update RetrospectiveProcessGroup Step

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

{
  "data": {
    "id": "53fd8672-7b0d-4311-8f66-384963820036",
    "type": "retrospective_process_group_steps",
    "attributes": {
      "retrospective_process_group_id": "5f0203d8-855d-46d3-9934-bccd40dd5ec9",
      "retrospective_step_id": "fa504a82-4889-49c6-a2f7-d225938cceec",
      "position": 2,
      "updated_at": "2026-02-13T18:09:31.301-08:00",
      "created_at": "2026-02-13T18:09:31.260-08:00"
    }
  }
}