Cancelled messages shouldn't be sent to Slack

I'm running SlackMC on my BungeeCord proxy which also has a plugin installed to prevent sending chat messages too fast. While cancelled messages don't show ingame, they are still sent to Slack.

[mastercoms]

Messages extend events in SlackMC 2.0, so advanced features that events provide are supported, and proper cancellation support is in SlackMC 2.0. This release will be released this week, or very early next week.