title: Symfony form - set DateType on Twig
body: <p>I have a problem with setting value in Symfony2.8 form via twig.
  I can set values for text elements by:</p>
  
  <pre><code>{{ form_widget(form.fieldName, {'attr': {'value': '50'}}) }}
  </code></pre>
  
  <p>I would like to do the same for DateType::class field. Already tried:</p>
  
  <pre><code>{{ form_widget(form.dateType, {'attr': {'value': '2020-10-30'}}) }}
  
  {{ form_widget(form.dateType, {'value': '2020-10-30'}) }}
  
  {{ form_widget(form.dateType, {'widget': '2020-10-30'}) }}
  
  {{ form_widget(form.dateType, {'value': '2020-10-30'|date('Y-m-d')}) }}
  
  {{ form_widget(form.dateType, {'attr': {'value': '2020-10-30'|date('Y-m-d')}}) }}
  
  {{ form_widget(form.dateType, {'attr': {'value': date('2020-10-30')}}) }}
  </code></pre>
  
  <p>Answers or references are appreciated.</p>