Retrieves an incident retrospective step

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

{
  "data": {
    "id": "55412b23-d64d-420f-99f3-6616d62dcba5",
    "type": "incident_retrospective_steps",
    "attributes": {
      "retrospective_step_id": "22b143f9-7b83-440c-b3b3-b3047e2d1ab0",
      "incident_id": "494556a8-4f59-4dc7-b751-9d2d1425a958",
      "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": "2025-11-24T17:28:25.598-08:00",
      "updated_at": "2025-11-24T17:28:25.598-08:00"
    }
  }
}