Import postmortem document

curl --request POST \
  --url https://api.incident.io/v2/incidents/{id}/actions/import_postmortem_document \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "content": "## Summary\n\nA database migration caused increased latency...",
  "title": "INC-123: Post-incident review"
}
'

{
  "postmortem_document": {
    "created_at": "2021-08-17T13:28:57.801578Z",
    "document_url": "https://app.incident.io/my-org/incidents/123/post-mortems/01GDZEW57FDA1K4S63MGMQ5DS9",
    "editors": [
      {
        "email": "lisa@incident.io",
        "id": "01FCNDV6P870EA6S7TK1DSYDG0",
        "name": "Lisa Karlin Curtis",
        "role": "viewer",
        "slack_user_id": "U02AYNF2XJM"
      }
    ],
    "exported_urls": [
      "https://www.notion.so/INC-123-sad-database",
      "https://docs.google.com/document/d/1234"
    ],
    "id": "01GDZEW57FDA1K4S63MGMQ5DS9",
    "incident_id": "01GBA8J19SMXQWPJMX3P2ESCVG",
    "status": "in_progress",
    "title": "INC-123: Database is sad",
    "updated_at": "abc123"
  }
}