Fix dns labels/names size limits

Author: nixawk

lib/net/dns/names/names.rb

@@ -46,8 +46,8 @@ def dn_expand(packet,offset)
       end
 
       def pack_name(name)
-        if name.size > 63
-          raise ArgumentError, "Label data cannot exceed 63 chars"
+        if name.size > 255
+          raise ArgumentError, "Name data cannot exceed 255 chars"
         end
         arr = name.split(".")
         str = ""