Creates a playbook task

curl --request POST \
  --url https://api.rootly.com/v1/playbooks/{playbook_id}/playbook_tasks \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/vnd.api+json' \
  --data '{
  "data": {
    "type": "playbook_tasks",
    "attributes": {
      "task": "<string>",
      "description": "<string>",
      "position": 123
    }
  }
}'

{
  "data": {
    "id": "0e9a4b22-d87e-47e8-bef7-035524c105a5",
    "type": "playbook_tasks",
    "attributes": {
      "playbook_id": "2fa36c6d-5a23-454d-8f34-029fdd616151",
      "task": "New task",
      "description": "New task description",
      "position": 1,
      "created_at": "2025-08-21T23:34:56.732-07:00",
      "updated_at": "2025-08-21T23:34:56.732-07:00"
    }
  }
}