title: Capybara find element value of aria-pressed
body: <p>I would like to get the value of aria-pressed for the below code in capybara:</p>
  
  <pre><code>&lt;button aria-pressed="true" class="btn btn-default active" data-active="true" data-toggle="button" id="grid-filter-invited-button" type="button"&gt;
    Invited
  &lt;/button&gt;
  </code></pre>
  
  <p>It's a button... when i click on it, its aria-pressed value toggles between true and false..I want the value of "aria-pressed". Can anyone please help?</p>