Fix purgecss configuration for new status behavior (#662)

Add all the attributes used for hiding skipped statuses to the purgecss
safelist to avoid stripping them from the stylesheet in production
builds. Because some of these values are dynamically generated, the
default logic didn't detect them.

postcss.config.js

@@ -15,9 +15,11 @@ module.exports = {
         defaultExtractor: content => {
           return content.match(/[\w-./]*\w/g) || [];
         },
-        // status classes are dynamically generated
         safelist: [
+          // status classes are dynamically generated
           "approved", "disapproved", "pending", "skipped", "error",
+          // keep all selectors that relate to hidden statuses
+          "data-next-status", "data-hide-status",
         ],
       }),
       cssnano({