Bump github.com/slack-go/slack from 0.18.0 to 0.20.0#430

dependabot[bot] wants to merge 1 commit intomainabahmed/kwatch:mainfrom

dependabot/go_modules/github.com/slack-go/slack-0.20.0abahmed/kwatch:dependabot/go_modules/github.com/slack-go/slack-0.20.0Copy head branch name to clipboard