set relativeTo option (to file directory) when passing css content into clean-css
set relativeTo option (to file directory) when passing css content into clean-css

HaNdTriX/gulp-minify-css,MichaelFBA/gulp-minify-css,keremciu/gulp-minify-css,webconnex/gulp-minify-css,mpath-development/gulp-minify-css,zarko-tg/gulp-minify-css,LoicMahieu/gulp-minify-css,sibrus/gulp-minify-css