Added Cask tower2 (#5877)
Added Cask tower2 (#5877)

Since Tower.app v3 has switched to subscriptions (booh!), adding this tower2 alternate version cask.

This is simply a copy of an older revision of the tower.rb cask from the homebrew-cask project, with cask name changed from ‘tower’ to ‘tower2’.
pkq/homebrew-versions,mahori/homebrew-versions,caskroom/homebrew-versions,rogeriopradoj/homebrew-versions,lantrix/homebrew-versions,Ngrd/homebrew-versions,lantrix/homebrew-versions,caskroom/homebrew-versions,mahori/homebrew-cask-versions,rogeriopradoj/homebrew-versions,victorpopkov/homebrew-versions,Ngrd/homebrew-versions,victorpopkov/homebrew-versions,404NetworkError/homebrew-versions,pkq/homebrew-versions,404NetworkError/homebrew-versions