[PHP-CS-Fixer] Remove PHP73Migration

Author: hlecorche

.php_cs.dist

@@ -23,7 +23,6 @@ return PhpCsFixer\Config::create()
         '@PHP56Migration:risky' => true,
         '@PHP71Migration' => true,
         '@PHP71Migration:risky' => true,
-        '@PHP73Migration' => true,
         'array_syntax' => ['syntax' => 'short'],
         'fopen_flags' => true,
         'header_comment' => ['header' => $fileHeaderComment, 'separate' => 'both'],