Block Kit not supported

[celloward]

Slack now uses Block Kit to richly format messages. This now seems to be the only way to format links with custom text but it also opens up many other features for messages. Lita-slack is not currently supporting this feature. I have a working solution on a fork which adds this functionality. I can't find official contribution guidelines, so should I just open a PR for this?

[tim-fitzgerald]

@celloward Im not involved with lita but I would benefit from your code change - could I ask you open a PR anyway or share your solution here? :)