update_channelsなどが動かない

[hakatashi]

{"ok"=>false, "error"=>"method_deprecated", "response_metadata"=>{"messages"=>["[ERROR] This method is retired and can no longer be used. Please use conversations.list or users.conversations instead. Learn more: https://api.slack.com/changelog/2020-01-deprecating-antecedents-to-the-conversations-api."]}}

conversations系のAPIに切り替える必要がある。