title: get auth0 user metadata as part of user information
body: <p>I don't find how to get the user_metadata from the Auth0 Authentication api:</p>
  
  <pre><code>$auth0Api = new Authentication($domain, $clientId, $clientSecret);
  
  $tokenInfo = $auth0Api-&gt;login([
      'username' =&gt; $username,
      'password' =&gt; $password,
      'realm' =&gt; 'Username-Password-Authentication',
  ]);
  $accessToken = $tokenInfo["access_token"];
  
  $info = $auth0Api-&gt;userinfo($accessToken);
  </code></pre>
  
  <p>The final <code>$info</code> array only contains the main user information, no meta_data at all. I tried creating a rule from the Auth0 side to add stuff to the user itself (doing <code>user.customtag = 'helloworld'</code> for example) and the customization does not show either.</p>
  
  <p>User info retrieved:</p>
  
  <pre><code>{
    "sub":"auth0|XXXX",
    "name":"XXXX@XXXX.com",
    "nickname":"XXXX",
    "picture":"XXXX.png",
    "updated_at":"2017-03-31T08:50:59.819Z",
    "email":"XXXX@XXXX.com",
    "email_verified":true
  }
  </code></pre>
  
  <p>The "Raw Json" tab of that user shows something much more complete:</p>
  
  <pre><code>{
      "email": "XXXX@XXXX.com",
      "email_verified": true,
      "user_id": "auth0|XXXX",
      "picture": "XXXX.png",
      "nickname": "XXXX",
      "identities": [
          {
              "user_id": "XXXX",
              "provider": "auth0",
              "connection": "Username-Password-Authentication",
              "isSocial": false
          }
      ],
      "updated_at": "2017-03-31T08:50:59.819Z",
      "created_at": "2017-03-23T16:03:47.075Z",
      "name": "XXXX",
      "user_metadata": {
          "languageCode": "EN"
      },
      "last_ip": "XXXX",
      "last_login": "XXXX",
      "logins_count": XXXX,
      "blocked_for": [],
      "guardian_enrollments": []
  }
  </code></pre>
  
  <p>How is it supposed to work?</p>
  
  <p>Environment:</p>
  
  <ul>
  <li>composer: "auth0/auth0-php": "~5.0"</li>
  <li>php 7.1</li>
  <li>Auth0 Free account</li>
  </ul>