Requirements have a dependency with an especific version of symfony/filesystem >= 4.4.17, this avoids installation if using earlier versions of Symfony.
I see this library is used just to dump code to disk, something that was present on earlier versions of symfony/filesystem, I have forked the project and tried symfony/filesystem:^3.4 to be exact 3.4.47 and it works fine, there is some reason to require '>= 4.4.17`?