script: fix deprecation warning in makeseeds.py

makeseeds.py:139: DeprecationWarning: please use dns.resolver.resolve() instead
  asn = int([x.to_text() for x in dns.resolver.query('.'.join(

per https://dnspython.readthedocs.io/en/latest/whatsnew.html
dns.resolver.query() was deprecated in dnspython version 2.0.0

contrib/seeds/makeseeds.py

@@ -135,7 +135,7 @@ def lookup_asn(net, ip):
             ipaddr = res.rstrip('.')            # 2.0.0.1.4.8.6.0.b.0.0.2.0.0.2.3
             prefix = '.origin6'
 
-        asn = int([x.to_text() for x in dns.resolver.query('.'.join(
+        asn = int([x.to_text() for x in dns.resolver.resolve('.'.join(
                    reversed(ipaddr.split('.'))) + prefix + '.asn.cymru.com',
                    'TXT').response.answer][0].split('\"')[1].split(' ')[0])
         return asn