Expose webhook url

In this example we see few fields which we can access

query {
  webhooks(board_id: 1234567890){
    id
    event
    board_id
    config
  }
}

It would be great if you also expose the url.

This would be useful to identify old webhooks which should be removed (but probably also other use cases)
Thanks

Thank you for your request @viso !!