title: Cannot update single Composer package
body: <p>My <code>composer.json</code></p>
  
  <pre><code>"require": {
      "php": "&gt;=5.5.9",
      "laravel/framework": "5.1.*",
      "laravelcollective/html": "~5.0",
      "laravel/cashier": "~5.0",
      "baum/baum": "~1.1",
      "laracasts/flash": "~1.3",
      "intervention/image": "^2.3",
      "toin0u/geocoder-laravel": "@stable",
      "torann/geoip": "0.2.*@dev"
  },
  </code></pre>
  
  <p>My <code>composer show -i</code></p>
  
  <pre><code>laravel/cashier                       v5.0.14            Laravel Cashier pr...
  laravel/framework                     v5.1.29            The Laravel Framew...
  </code></pre>
  
  <p>Newest Laravel/Cashier version is 6.0.<br>
  If I run <code>composer update laravel/cashier</code> I get </p>
  
  <blockquote>
    <p>Nothing to install or update.  </p>
  </blockquote>
  
  <p>If I modify my <code>composer.json</code> to <code>"laravel/cashier": "~6.0"</code> and run <code>composer install</code> I get </p>
  
  <blockquote>
    <p>... Lock file is not up to date ... and Nothing to install or update.  </p>
  </blockquote>
  
  <p>What is the recommended way of updating a package and why wouldn't <code>composer update larave/cashier</code> work?</p>