Remove dead link to resolver test

matje · matje · commit 8e78f8fc0f9a · 2023-03-29T15:28:10.000+02:00
The doc file doc/dnssec-guide/validation.rst points to a resolver test
site that is now down. Remove the dead link.
diff --git a/doc/dnssec-guide/validation.rst b/doc/dnssec-guide/validation.rst
@@ -112,8 +112,6 @@ confirm that it is in fact validating DNS responses.
 
 -  `Internet.nl <https://en.conn.internet.nl/connection/>`__
 
--  `DNSSEC Resolver Test (uni-due.de) <https://dnssec.vs.uni-due.de/>`__
-
 -  `DNSSEC or Not (VeriSign) <https://www.dnssec-or-not.com/>`__
 
 .. _using_dig_to_verify:
