title: Maximaze window from qt designer
body: <p>Every time i change something in .ui file from qt designer, then i compile with pyuic5 command.</p>
  <p>Then i put <code>MainWindow.showMaximized()</code> instead of <code>MainWindow.show()</code> command.</p>
  <p>Is there any way to do it from Qt Designer?</p>