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": "39e327fd-515c-4d32-914d-e6d3102b532b",
    "type": "retrospective_process_group_steps",
    "attributes": {
      "retrospective_process_group_id": "ab0ec089-f285-4971-93a2-01f96d141d07",
      "retrospective_step_id": "0f0aab4b-e015-4252-b31a-209d02299059",
      "position": 2,
      "updated_at": "2025-09-18T00:29:03.624-07:00",
      "created_at": "2025-09-18T00:29:03.565-07:00"
    }
  }
}