Retrieves a Retrospective Process Group

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

{
  "data": {
    "id": "bf61db20-e6e1-43dd-94a1-022cf7ce8d57",
    "type": "retrospective_process_groups",
    "attributes": {
      "retrospective_process_id": "36e69b6a-f1b5-4eda-af9b-8829aad874c0",
      "sub_status_id": "e9efcecf-d423-44b9-9ff5-090d543817d0",
      "position": 1,
      "updated_at": "2025-09-22T15:33:41.127-07:00",
      "created_at": "2025-09-22T15:33:41.127-07:00"
    },
    "relationships": {
      "retrospective_process_group_steps": {
        "data": []
      }
    }
  }
}