Retrieves an incident retrospective step

curl --request GET \
  --url https://api.rootly.com/v1/incident_retrospective_steps/{id} \
  --header 'Authorization: Bearer <token>'

{
  "data": {
    "id": "5bca9139-767a-4255-97d0-2a532e1daee4",
    "type": "incident_retrospective_steps",
    "attributes": {
      "retrospective_step_id": "61191a78-4b58-4d01-b49c-46ab5896b10d",
      "incident_id": "cb5a6b88-2d4a-4a8c-a9bf-fab78fc0155f",
      "title": "Step 4",
      "description": null,
      "due_date": null,
      "user_id": null,
      "kind": "custom",
      "position": 1,
      "skippable": false,
      "status": "todo",
      "status_changed_at": null,
      "status_changed_by_id": null,
      "created_at": "2025-09-23T07:26:01.563-07:00",
      "updated_at": "2025-09-23T07:26:01.563-07:00"
    }
  }
}