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": "b2a1a617-d1bb-489d-96f6-63bf88e5f0e4",
    "type": "retrospective_process_group_steps",
    "attributes": {
      "retrospective_process_group_id": "1049a8dc-d2b8-44fe-8125-a49916224afb",
      "retrospective_step_id": "b9bc9261-7a47-45ac-ace2-dd4dd29e934a",
      "position": 2,
      "updated_at": "2025-12-03T21:32:26.191-08:00",
      "created_at": "2025-12-03T21:32:26.151-08:00"
    }
  }
}