@slack/interactive-messages@1.2.0

• Convert @slack/interactive-messages to TypeScript (#799) - thanks @clavin.
  • This package is still meant to be used by JavaScript developers!
• Bump interactive-messages deps to fix security warnings (#812) - thanks @seratch.
• Fixes broken links to local development tutorial (#774) - thanks @aoberoi.
• Increase test timeout multipliers (#840) - thanks @clavin.