Relax the RegEx restrictions to allow the new ICAAN TLDs.

mongoengine/fields.py

@@ -160,8 +160,8 @@ class EmailField(StringField):
         r"(^[-!#$%&'*+/=?^_`{}|~0-9A-Z]+(\.[-!#$%&'*+/=?^_`{}|~0-9A-Z]+)*"
         # quoted-string
         r'|^"([\001-\010\013\014\016-\037!#-\[\]-\177]|\\[\001-011\013\014\016-\177])*"'
-        # domain
-        r')@(?:[A-Z0-9](?:[A-Z0-9-]{0,253}[A-Z0-9])?\.)+[A-Z]{2,6}$', re.IGNORECASE
+        # domain (max length of an ICAAN TLD is 22 characters)
+        r')@(?:[A-Z0-9](?:[A-Z0-9-]{0,253}[A-Z0-9])?\.)+[A-Z]{2,22}$', re.IGNORECASE
     )
 
     def validate(self, value):