List incident retrospectives

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

{
  "data": [
    {
      "id": "<string>",
      "type": "incident_post_mortems",
      "attributes": {
        "title": "<string>",
        "created_at": "<string>",
        "updated_at": "<string>",
        "content": "<string>",
        "status": "draft",
        "started_at": "<string>",
        "mitigated_at": "<string>",
        "resolved_at": "<string>",
        "show_timeline": true,
        "show_timeline_trail": true,
        "show_timeline_genius": true,
        "show_timeline_tasks": true,
        "show_timeline_action_items": true,
        "show_timeline_order": "desc",
        "show_services_impacted": true,
        "show_functionalities_impacted": true,
        "show_groups_impacted": true,
        "show_alerts_attached": true,
        "url": "<string>"
      }
    }
  ],
  "links": {
    "self": "<string>",
    "first": "<string>",
    "prev": "<string>",
    "next": "<string>",
    "last": "<string>"
  }
}