title: How would I only update one composer dependency?
body: <p>I expected that</p>
  
  <pre><code>composer update videlalvaro/php-amqplib
  </code></pre>
  
  <p>would only update one dependency, but instead of that it updates all.</p>
  
  <p>What am I missing?</p>
  
  <p>PS: this dependency is defined as <code>"videlalvaro/php-amqplib": "2.2.0"</code> in <code>composer.json</code></p>
  
  <p>PPS: the composer version used is <code>3da05c68f9561fa822c522b1815435ff990493ff 2013-10-02 14:25:06</code></p>
  
  <p>PPPS: the actual output:</p>
  
  <pre><code>$ composer.phar update videlalvaro/php-amqplib --no-dev
  Loading composer repositories with package information
  Updating dependencies
  Your requirements could not be resolved to an installable set of packages.
  
    Problem 1
      - symfony/icu v1.2.0 requires lib-icu &gt;=4.4 -&gt; the requested linked library icu has the wrong version installed or is missing from your system, make sure to have the extension providing it.
      - symfony/icu v1.2.0 requires lib-icu &gt;=4.4 -&gt; the requested linked library icu has the wrong version installed or is missing from your system, make sure to have the extension providing it.
      - Installation request for symfony/icu == 1.2.0.0 -&gt; satisfiable by symfony/icu[v1.2.0].
  </code></pre>