feat: Webhook Notification Types

[davidgrayston-paddle]

Added

Paddle\SDK\Notifications\Notification and subtypes, e.g. Paddle\SDK\Notifications\Events\TransactionUpdated

Usage

use Paddle\SDK\Notifications\Notification;
use Paddle\SDK\Notifications\Notification\TransactionUpdatedNotification;

$notification = Notification::fromRequest($request);
$id = $notification->id;
$eventId = $notification->eventId;
$eventType = $notification->eventType;
$occurredAt = $notification->occurredAt;

if ($notification instanceof TransactionUpdatedNotification) {
    $transactionId = $notification->transaction->id;
}

[davidgrayston-paddle]

Superseded by #74