How we can help user with different event versions?

Should we provide some meta information about an event? For example:
We have a legacy system and want to send a new payload in events. We can create something like this:

```ruby
events = Hanami::Events.build(:kafka)
events.subscribe('*', version: 1.0) { |payload| error 'Old event payload' }
events.subscribe('*', version: 2.0) { |payload| Handler.call(payload) }

events.broadcast('user.updated', version: 2.0, user_id: 1)
```