Would it be acceptable to include the following features to this repo?

• https://www.twilio.com/docs/sendgrid/api-reference/webhooks
• https://www.twilio.com/docs/sendgrid/for-developers/tracking-events/getting-started-event-webhook

Based on the current designed Webhook client, it appears that a new client would need to be created for the Webhook client.

Additionally, adding this option would introduce Swift Crypto as a dependency for signed events.