Add Zend_Feed to the list of obsolete classes

Author: Ben Batschelet

dev/tests/static/testsuite/Magento/Test/Legacy/_files/obsolete_classes.php

@@ -4220,4 +4220,5 @@
     ['Magento\Framework\MessageQueue\Config\Reader', 'Magento\Framework\MessageQueue\Config\Reader\Xml'],
     ['Magento\Framework\MessageQueue\PublisherFactory'],
     ['Magento\Framework\MessageQueue\PublisherProxy'],
+    ['Zend_Feed', 'Zend\Feed'],
 ];