title: Cannot change permission or delete /root/.composer directory
body: <p>Here is the scenario. I have a PHP Docker with the Composer installed, then I tried to use composer package from other repositories and do a composer update. I got the following error:</p>
  
  <blockquote>
    <p>Cannot create cache directory /root/.composer/cache/repo/https---packagist.org/, or directory is not writable. Proceeding without cache</p>
  </blockquote>
  
  <p>I know something wrong with /root/.composer directory.
  I tried to change the permission and delete it, but I couldn't:</p>
  
  <p><a href="https://i.stack.imgur.com/Qqnpm.png" rel="nofollow noreferrer">Here is the screenshot</a></p>
  
  <p>Basically, I cannot do anything with "/root/.composer".
  How can I change permission or delete this folder?</p>