v0.7.3

Thank you for all the contributions!

Fixes

• Resolve: Revert changes to json tags in Attachment's Text field #788 by @prgres
• Use custom ctx on SetUserCustomStatusContext #830 by @GLOFonseca
• reminders time field fix #843 by @KarolisKl
• Fix unintended json marshalling error #854 by @kanata2

Improvements

• Add test for EscapeMessage function in slack #833 by @sryoya
• add missing result evaluation in bot test #842 by @sryoya
• Add conversations.list to the slacktest server #853 by @hobbeswalsh
• adds support for listing files hidden by the free tier file limit #846 by @rk295

Miscs

• Add deprecation comments to channels., groups., im.* #815 by @kanata2
  • see also: https://api.slack.com/changelog/2020-01-deprecating-antecedents-to-the-conversations-api
• Use golangci-lint and GitHub Actions #840 by @kanata2
• Remove configuration for Travis CI #855 by @kanata2