Retrieves an incident retrospective step

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

{
  "data": {
    "id": "d05043da-875e-4718-b364-92a276a6fcbe",
    "type": "incident_retrospective_steps",
    "attributes": {
      "retrospective_step_id": "65589e6c-0306-4647-bfb0-d35bd61b3ae8",
      "incident_id": "0a397f1a-c7bc-4e93-abc1-dd2528049ccf",
      "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": "2025-12-15T12:22:29.191-08:00",
      "updated_at": "2025-12-15T12:22:29.191-08:00"
    }
  }
}