Run tests on PHP 8.3, fix dynamic property for PHP 8.2 and update test suite

[yadaiio]

Builds on top of #32, #37 and #39.

References: https://github.com/reactphp/socket/pull/300, https://github.com/clue/reactphp-zenity/pull/63, https://github.com/clue/reactphp-csv/pull/33 and others.

The tests were failing in PHP 5.3 because of an unknown React\Promise\Timer\sleep() function. In order to avoid this I updated this to use the React\Async\delay() function instead.

Additionally I saw the dynamic properties were deprecated since PHP 8.2, see https://www.php.net/releases/8.2/en.php#deprecate_dynamic_properties, so I had to add a new class variable in the CompositeConnection.php file to avoid that the test for PHP 8.2 and PHP 8.3 run infinitely.