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": "b92ed365-c005-4265-8ac0-4f7d4ddeb2b2",
    "type": "retrospective_process_group_steps",
    "attributes": {
      "retrospective_process_group_id": "797bda73-014f-47a3-af68-427716c49593",
      "retrospective_step_id": "541a7820-dada-4a1a-8f56-31b1e786d326",
      "position": 2,
      "updated_at": "2026-01-16T12:43:38.294-08:00",
      "created_at": "2026-01-16T12:43:38.245-08:00"
    }
  }
}