Update airmail-beta to 4.0,456 (#8481)
Update airmail-beta to 4.0,456 (#8481)

* Update airmail-beta to 4.0,456

Include mctoken in version as it will be needed when downloading old version。

* Update airmail-beta.rb

* Update airmail-beta.rb

404NetworkError/homebrew-versions,mahori/homebrew-cask-versions,rogeriopradoj/homebrew-versions,pkq/homebrew-versions,caskroom/homebrew-versions,caskroom/homebrew-versions,pkq/homebrew-versions,rogeriopradoj/homebrew-versions,lantrix/homebrew-versions,404NetworkError/homebrew-versions,lantrix/homebrew-versions