Compatibility issue with Symfony 5

[Berdir]

If you have symfony/console 5.x installed globally/for composer, then you get the following error:

Fatal error: Uncaught TypeError: Return value of "Ayesh\ComposerPreload\Composer\Command\PreloadCommand::execute()" must be of the type int, "null" returned. vendor/symfony/console/Command/Command.php:259

Needs to add a return 0;