title: Django admin. Hide field on change select field
body: <p>I have model:</p>
  
  <pre><code>class CategoryField(models.Model):
      selectfield = models.IntegerField(choices=SELECT_FIELD_CHOICES, default=1)
      verified = models.BooleanField(default=True, verbose_name='Required?')
  </code></pre>
  
  <p>In admin page I have <code>selectField</code> with choices: "value1", "value2", "value3", ...
  When I select "value2" I need to show <code>verified</code> field. How can I do it?</p>