title: Unable to save empty list to Django ArrayField
body: <p>I have a Django model</p>
  <pre><code>from django.db import models
  from django.contrib.postgres.fields import ArrayField
  
  
  class Website(models.Model):
      id = models.BigAutoField(primary_key=True, verbose_name='ID')
      status = models.BooleanField(default=True)
      meta = ArrayField(base_field=models.CharField(max_length=200, null=True), default=list)
  
  </code></pre>
  <p>I'm using following serializer to save data to the DB:</p>
  <pre><code>class WebsiteConfigSerializer(serializers.ModelSerializer):
      class Meta:
          model = Website
          fields = ('status', 'meta')
  </code></pre>
  <p>When I'm trying to save the following data, I'm getting error:</p>
  <pre><code>{
      &quot;status&quot;: true,
      &quot;meta&quot;: []
  }
  
  #ERROR:
  # &quot;meta : This list may not be empty.&quot;
  </code></pre>
  <p>Is it not possible to save an empty list to an <code>ArrayField</code> ?
  When I'm not passing the field at all, the value getting stored is <code>{NULL}</code>.
  Also during initial migrations, since I had added a <code>default</code> value as <code>list</code>, all my existing entries had &quot;meta&quot; value as <code>{}</code></p>
  <p>If the  empty list value is not allowed at all, how come this got saved during initial migration ?</p>