php 8.1: vfsStreamDirectory::getIterator() incompatible with IteratorAggreate

[othercorey]

A new php 8.1 warning about incompatible return types.

PHP Fatal error:  During inheritance of IteratorAggregate: Uncaught Return type of org\bovigo\vfs\vfsStreamDirectory::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[ReturnTypeWillChange] attribute should be used to temporarily suppress the notice

/home/runner/work/cakephp/cakephp/vendor/mikey179/vfsstream/src/main/php/org/bovigo/vfs/vfsStreamDirectory.php:248
/home/runner/work/cakephp/cakephp/vendor/mikey179/vfsstream/src/main/php/org/bovigo/vfs/vfsStreamDirectory.php:16
/home/runner/work/cakephp/cakephp/vendor/mikey179/vfsstream/src/main/php/org/bovigo/vfs/vfsStream.php:360
/home/runner/work/cakephp/cakephp/vendor/mikey179/vfsstream/src/main/php/org/bovigo/vfs/vfsStream.php:167

I would have opened a PR, but wasn't sure if you wanted to change the return type or suppress the warning.