fix build issue

Signed-off-by: kerthcet <[email protected]>

Author: kerthcet

config/postcss.config.js

@@ -1,5 +1,5 @@
 const autoprefixer = require('autoprefixer');
-const purgecss = require('@fullhuman/postcss-purgecss');
+const purgecss = require('@fullhuman/postcss-purgecss').default;
 const whitelister = require('purgecss-whitelister');
 
 module.exports = {