Update libreoffice-still to 6.1.5 (#6955)
Update libreoffice-still to 6.1.5 (#6955)


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