generate a new rule object, by using the make:rule Artisan command.
  Let's use this command to generate a rule that verifies a string is 
  uppercase. Laravel will place the new rule in the app/Rules directory.
  If this directory does not exist, Laravel will create it when you 
  execute the Artisan command to create your rule:
  
  php artisan make:rule Uppercase
  
  go to https://laravel.com/docs/8.x/validation#custom-validation-rules
  for details