fix: Warning: Running "imagemin:dist" (imagemin) task Fatal error: Cannot read property 'contents' of undefined

Warning: Running "imagemin:dist" (imagemin) task

Fatal error: Cannot read property 'contents' of undefined

https://github.com/gruntjs/grunt-contrib-imagemin/issues/333

changed the grunt-contrib-imagemin version to 1.0.0 and imagemin version to 4.0.0, as below prcture

Undefined mixin 'clearfix' / npm install bower install grunt

    directory .tmp/styles

        error app/styles/main.scss (Line 104 of app/styles/_product.scss: Undefined mixin 'clearfix'.)

@mixin clearfix() {
&:before,
&:after {
content: ' '; // 1
display: table; // 2
}
&:after {
clear: both;
}
*zoom: 1; // Trigger IE6/7 'hasLayout'
}