fixed typo

src/Composer/Command/UpdateCommand.php

@@ -33,7 +33,7 @@ class UpdateCommand extends Command
                 new InputOption('prefer-source', null, InputOption::VALUE_NONE, 'Forces installation from package sources when possible, including VCS information.'),
                 new InputOption('dry-run', null, InputOption::VALUE_NONE, 'Outputs the operations but will not execute anything (implicitly enables --verbose).'),
                 new InputOption('dev', null, InputOption::VALUE_NONE, 'Enables installation of dev-require packages.'),
-                new InputOption('no-custom-installers', null, Input::VALUE_NONE, 'Disables all custom installers.'),
+                new InputOption('no-custom-installers', null, InputOption::VALUE_NONE, 'Disables all custom installers.'),
                 new InputOption('no-scripts', null, InputOption::VALUE_NONE, 'Skips the execution of all scripts defined in composer.json file.'),
             ))
             ->setHelp(<<<EOT