Add no_unused_import rule to PHP CS Fixer (#1537)

Author: romainneutron

.php-cs-fixer.dist.php

@@ -13,6 +13,7 @@
     ->setRules([
         '@PER-CS' => true,
         '@PHP84Migration' => true,
+        'no_unused_imports' => true,
     ])
     ->setFinder($finder)
 ;