composer出現404錯誤

composer update 的時候出現：

[Composer\Downloader\TransportException]
The "https://packagist.org/p/provider-2018-10%24ceed846c1a187d8670540d62ead2c32137653431a06bf2c84d5fb2e04ed484b5.json" file could not be downloaded (HTTP/1.1 404 Not Found)

解決方法：
執行composer clear-cache