Callback implementation for Webhoox.Adapter.handle_webhook/3.

Handles an s3 compatible webhook:

• https://docs.aws.amazon.com/AmazonS3/latest/userguide/notification-how-to-event-types-and-destinations.html
• https://docs.aws.amazon.com/AmazonS3/latest/userguide/notification-content-structure.html
• https://docs.min.io/docs/minio-bucket-notification-guide.html