Switch back to the parent page

After clicking the install button, we need to switch back out of the
iframe to the parent page, or else the web driver will be looking for
the ‘Updated!’ message inside of the iframe, and so the tests will fail.

See #6

tests/codeception/acceptance/update-wordpoints.Cept.php

@@ -16,6 +16,7 @@
 $I->see( 'Commit Log' );
 $I->see( 'Last Updated:' );
 $I->click( 'Install Update Now' );
+$I->switchToIFrame();
 $I->waitForJqueryAjax();
 $I->see( 'Updated!' );