Remove mayo from drupal9

cf:　https://www.drupal.org/docs/theming-drupal/defining-a-theme-with-an-infoyml-file

1. mkdir ~/public_html/drupal9/web/themes/contrib/mayo
   
2. cd ~/public_html/drupal9/web/themes/contrib/mayo
3. vim mayo.info.yml with the following lines:
   

   name: Mayo
   type: theme
   description: 'remove mayo'
   core_version_requirement: ^9
   libraries:
     - mayo/l
   base theme: stable9
   regions:
     header: 'Header'
     content: 'Content'
     sidebar_first: 'Sidebar first'
     footer: 'Footer'
   

4. touch mayo.l
   
5. Go into admin/appearance 首頁->　管理->　外觀
   There sould be a Myao theme. Delete it. Done!
6. If Mayo theme not appear, then this method not work.