chore: update examples

Author: billyyyyy3320

examples/directory-classifier/.vuepress/config.js

@@ -34,9 +34,6 @@ module.exports = {
       globalPagination: {
         lengthPerPage: 5
       },
-      sitemap: {
-        hostname: 'https://yourdomain'
-      },
       comment: {
         service: 'disqus',
         shortname: 'vuepress-plugin-blog',