chore(package): update imagemin-pngquant to version 8.0.0

package.json

@@ -53,7 +53,7 @@
     "gulp-uglify": "^3.0.2",
     "gulp-zip": "^4.2.0",
     "imagemin-mozjpeg": "^8.0.0",
-    "imagemin-pngquant": "^7.0.0",
+    "imagemin-pngquant": "^8.0.0",
     "run-sequence": "^2.2.0",
     "stylefmt": "^6.0.3",
     "stylelint": "^10.0.1",