Update julia-nightly to 0.7 (#5304)
Update julia-nightly to 0.7 (#5304)

* Update julia-nightly to 0.7.0-e4b6677561

* Update julia-nightly.rb

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