Description:
This is an issue found when configuring notification for a repository, after create new notification as "Repository Mirror Success " and "Repository Mirror Started", in the post request to webhook, in the received request content, there's no event type, see the weekhook request sent by Quay for reference.

Steps:
1. Login Quay
2. Create new repository
3. Configure new repository as mirror status
4. Create new notifications as "Repository Mirror Success " and "Repository Mirror Started"
5. Choose notification as "Webhook POST"
6. Save configurations
7. Trigger mirror sync up

Expected Results:
In the Webhook request, users can see the event type. like "Repository Mirror Success " or "Repository Mirror Started"

Actual Results:
In the Webhook request, users can NOT see the event type