make DumpFixer compatible for PHPCSFixer

[rugbymauri]

DumpFixer should adopt the methods used by https://github.com/kubawerlos/php-cs-fixer-custom-fixers/tree/main

• return a correct fixer name
• create a Fixers class which return a collection of Fixers .. https://github.com/kubawerlos/php-cs-fixer-custom-fixers/blob/main/src/Fixers.php