Provide Support for JSON payload when subscribing webhooks to ticket/messaging events

Zendesk recently released the ability to subscribe webhooks to certain events that occur within Zendesk (https://support.zendesk.com/hc/en-us/articles/9071412067738-Announcing-the-ability-to-subscribe-webhooks-to-ticket-and-messaging-events) which was a great feature to see implemented. However, we've quickly noticed that any value we could extract from this feature is negated by the fact that we cannot construct our own payload to send to our Webhook.

An example use case for us is to subscribing to new article publication events. We'd like to send a request to a Slack endpoint (which requires a specifically formatted request body/payload) in order to create a feed of updates in Slack whenever a new article is published. Because we cannot customize the payload, this isn't possible.

It'd be great to be able to send custom payloads to webhooks when subscribing to events, much like we can already do in Triggers for certain ticket updates, so that we can easily integrate with any platform we need.