Update dependencies and devDependencies
Update dependencies and devDependencies

updated: gulp-util, through2, bufferstreams, mocha. proxyquire and gulp

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