update css min package

gulpfile.js

@@ -17,7 +17,7 @@ const postcss = require('gulp-postcss')
 const sass = require('gulp-sass')
 const autoprefixer = require('autoprefixer')
 const concat = require('gulp-concat')
-const cssmin = require('gulp-cssmin')
+const cleanCSS = require('gulp-clean-css')
 
 const imagemin = require('gulp-imagemin')
 const mozjpeg = require('imagemin-mozjpeg')
@@ -109,7 +109,7 @@ gulp.task('css', function () {
     ]))
     .pipe(concat('style.css'))
     .pipe(gulpIf(config.env.dev, sourcemaps.write()))
-    .pipe(gulpIf(config.env.prod, cssmin()))
+    .pipe(gulpIf(config.env.prod, cleanCSS()))
     .pipe(gulp.dest('dist/css/'))
 })
 

package.json

@@ -40,8 +40,8 @@
     "eslint-plugin-promise": "^4.1.1",
     "eslint-plugin-standard": "^4.0.0",
     "gulp": "^3.9.1",
+    "gulp-clean-css": "^4.2.0",
     "gulp-concat": "^2.6.1",
-    "gulp-cssmin": "^0.2.0",
     "gulp-eslint": "^5.0.0",
     "gulp-if": "^2.0.2",
     "gulp-imagemin": "^4.1.0",