title: Github Issue 'locked' event doesn't update the Issue itself
body: <p>I'm using <a href="https://developer.github.com/v3/" rel="noreferrer">GitHub API v3</a> to connect to a <code>repository</code> and get the list of issues that were update/created <code>since</code> a specific <strong>date</strong>. I use these <a href="https://developer.github.com/v3/issues/#parameters" rel="noreferrer">parameters</a> to get a filtered result:</p>
  
  <ul>
  <li>filter: all </li>
  <li>labels: bug </li>
  <li>state: all </li>
  <li>sort: updated </li>
  <li>direction: ascendent</li>
  <li>since: <strong>date</strong></li>
  </ul>
  
  <p>If i find any result, for each issue I get the <a href="https://developer.github.com/v3/issues/events/" rel="noreferrer">issue events</a> that triggered a change (filtering for the ones that happened <code>since</code> <strong>date</strong>).</p>
  
  <p>Everything works fine for every <code>issue event</code> except for <strong>locked</strong> and <strong>unlocked</strong>
  events that, for some reason, don't update the issue <code>updated</code> field. </p>
  
  <p>This leads to the inability to get then the list of issues that were updated <code>since</code> that specific <strong>date</strong> and therefore I don't check for the <code>issue events</code>.</p>
  
  <p>Questions:</p>
  
  <ol>
  <li>Is there a reason why these two events don't update the issue?</li>
  <li>Is there an acceptable solution, except for the one where I should get all the issues and query them manually?</li>
  </ol>