title: Yii2: kartik/DateTimePicker prevent selection of a date before today
body: <p>I have tried with below code and it is not working for me.</p>
  
  <pre><code>echo $form-&gt;field($model, 'value')-&gt;widget(DateTimePicker::classname(), [
        'pluginOptions' =&gt; [
             'autoclose'      =&gt; true,
             'format'         =&gt; 'yyyy-mm-dd HH:ii:ss',
             'minuteStep'     =&gt; 1,
             'todayHighlight' =&gt; true,
             'startDate'      =&gt; date("y-m-d H:i:s"),
             'changeYear'     =&gt; true,
             'changeMonth'    =&gt; true,
        ]
  ])-&gt;label('Select date &amp; time');
  </code></pre>