Use correct purgecss conf

Author: ukutaht

purgecss.config.js

@@ -1,5 +1,5 @@
 module.exports = {
   content: ["./_site/**/*.html"],
-  css: ["./_site/css/site.css"],
+  css: ["./_site/assets/css/style.css"],
   defaultExtractor: content => content.match(/[\w-/.:]+(?<!:)/g) || []
 };