title: How to customize screen resolution with saucelabs (selenium, behat3.0 mink) capabilities
body: <p>This is my behat.yml file :</p>
  
  <pre><code>firefox:                  
   suites:  
      firefox:  
        contexts:  
          -FeatureContext
    extensions:  
      Behat\MinkExtension:
        javascript_session: selenium2
        base_url: https://example.com
        selenium2:
          wd_host: username:pwd@ondemand.saucelabs.com/wd/hub
          browser: firefox
          capabilities: {'platform':'OS X 10.10', 'browser':'firefox', 'version':'42.0', "screen-resolution":"1280x1024"}
  </code></pre>
  
  <p>Which is giving error "</p>
  
  <p>[Symfony\Component\Config\Definition\Exception\InvalidConfigurationException]<br>
    Unrecognized option "screen-resolution" under "testwork.mink.sessions.selenium2.selenium2.capabilities"</p>
  
  <p>I have tried this 
  <a href="https://groups.google.com/forum/#!topic/behat/kApbLIiAkOg" rel="nofollow">https://groups.google.com/forum/#!topic/behat/kApbLIiAkOg</a>, but I am also getting exactly same error.</p>
  
  <p>If I configure SauceLabsDriver then only I will get all (<a href="https://github.com/Behat/MinkExtension/blob/master/doc/index.rst#sessions" rel="nofollow">https://github.com/Behat/MinkExtension/blob/master/doc/index.rst#sessions</a>) - special flavor of the Selenium2Driver </p>
  
  <p>The above document is suggesting modify your behat.yml profile:</p>
  
  <pre><code>default:
      extensions:
          Behat\MinkExtension:
              sessions:
                  my_session:
                      sauce_labs: ~
  </code></pre>
  
  <p>But no idea how to implementing this. Any idea? How to change behat.yml file with saucelabs to use all those customization parameters.</p>