Update configuration.rst (#5576)

CONTRIBUTORS.rst

@@ -405,6 +405,7 @@ Contributors
 * Kiril Staikov
 * Saptak Sengupta
 * Dawid Bugajewski
+* Dawn Wages
 
 Translators
 ===========

docs/advanced_topics/api/v2/configuration.rst

@@ -159,7 +159,7 @@ JSON format. You can override the serialiser for any field using the
 
         api_fields = [
             # Change the format of the published_date field to "Thursday 06 April 2017"
-            APIField('published_date', serializer=DateField(format='%A $d %B %Y')),
+            APIField('published_date', serializer=DateField(format='%A %d %B %Y')),
             ...
         ]