Update dropbox-beta to 39.3.48 (#4738)
Update dropbox-beta to 39.3.48 (#4738)

* Update dropbox-beta to 39.3.48

* Update dropbox-beta.rb

* Update dropbox-beta.rb

* launchctl

* remove `icns`

caskroom/homebrew-versions,Ngrd/homebrew-versions,victorpopkov/homebrew-versions,mahori/homebrew-cask-versions,victorpopkov/homebrew-versions,lantrix/homebrew-versions,rogeriopradoj/homebrew-versions,pkq/homebrew-versions,mahori/homebrew-versions,pkq/homebrew-versions,404NetworkError/homebrew-versions,FinalDes/homebrew-versions,lantrix/homebrew-versions,rogeriopradoj/homebrew-versions,yurikoles/homebrew-versions,FinalDes/homebrew-versions,caskroom/homebrew-versions,404NetworkError/homebrew-versions,yurikoles/homebrew-versions,Ngrd/homebrew-versions