Fix CS

Author: ondrejmirtes

src/Rules/RuleLevelHelper.php

@@ -21,7 +21,6 @@
 use PHPStan\Type\TypeTraverser;
 use PHPStan\Type\TypeUtils;
 use PHPStan\Type\UnionType;
-use PHPStan\Type\VerbosityLevel;
 use function count;
 use function sprintf;