Merge pull request #167 from acgotaku/greenkeeper/imagemin-pngquant-7.0.0

Update imagemin-pngquant to the latest version 🚀

package.json

@@ -53,7 +53,7 @@
     "gulp-uglify": "^3.0.1",
     "gulp-zip": "^4.2.0",
     "imagemin-mozjpeg": "^8.0.0",
-    "imagemin-pngquant": "^6.0.0",
+    "imagemin-pngquant": "^7.0.0",
     "run-sequence": "^2.2.0",
     "stylelint": "^9.6.0",
     "stylelint-config-sass-guidelines": "^5.2.0",