我想在launching上安装CakePHP：
composer self-update && composer create-project --prefer-dist cakephp/app my_app_name
我收到此错误消息：
[Composer\Downloader\FilesystemException]
Filesystem exception:
Composer update failed: the "/home/myself/.composer/cache" directory use
d to download the temp file could not be written
如何解决？