Add CAA type for tests

Add CAA type for mock

Author: jwaguet

DnsMock.php

@@ -30,6 +30,7 @@ class DnsMock
         'NAPTR' => \DNS_NAPTR,
         'TXT' => \DNS_TXT,
         'HINFO' => \DNS_HINFO,
+        'CAA' => \DNS_CAA,
     ];
 
     /**