Add missing use

src/Composer/Downloader/ArchiveDownloader.php

@@ -13,6 +13,7 @@
 namespace Composer\Downloader;
 
 use Composer\Package\PackageInterface;
+use Composer\Util\Platform;
 use Symfony\Component\Finder\Finder;
 use React\Promise\PromiseInterface;
 use Composer\DependencyResolver\Operation\InstallOperation;