[@types/stripe] Fixed StripeWebhookEvent.created to be a number

The data received by a webhook endpoint is an almost identical object to the [Event Object](https://stripe.com/docs/api#event_object-created).

types/stripe/index.d.ts

@@ -3627,7 +3627,7 @@ declare namespace Stripe {
             id: string;
             object: string;
             api_version: string;
-            created: Date;
+            created: number;
             data: {
               object: T;
             };