title: Remove repositories from composer command line
body: <p>My project had a dependency that was on github, so when I installed it I ran</p>
  
  <pre><code>$ composer config repositories.vendor/package vcs https://github.com/vendor/package.git
  $ composer require vendor/package
  </code></pre>
  
  <p>Now, I need to remove that package.<br>
  If I just run <code>$ composer remove vendor/package</code> the "repositories" section is still in my <code>composer.json</code> file.</p>
  
  <pre><code>"repositories": {
  
          "type": "vcs",
          "url": "https://github.com/vendor/package.git"
      },
  </code></pre>
  
  <p>How can I also remove the "repositories" section from the command line?</p>