title: How to set min value DateTimeType [Symfony]
body: <p>I want to set the minimal date in input date    </p>
  
  <pre><code>$builder-&gt;add('dateRdv', DateTimeType::class,['data'   =&gt; new \DateTime(),
                  'attr'   =&gt; ['min' =&gt; new \DateTime()]])
  </code></pre>
  
  <p>Error is : </p>
  
  <blockquote>
    <p>An exception has been thrown during the rendering of a template
    ("Catchable Fatal Error: Object of class DateTime could not be
    converted to string").</p>
  </blockquote>
  
  <p>**</p>