docs: update several URLs to point to docs.named-data.net

Change-Id: If000753573c6a50130dc3101a411b6d482ccf3ed
diff --git a/docs/release-notes/release-notes-0.6.0.rst b/docs/release-notes/release-notes-0.6.0.rst
index da66436..904eb1d 100644
--- a/docs/release-notes/release-notes-0.6.0.rst
+++ b/docs/release-notes/release-notes-0.6.0.rst
@@ -16,7 +16,7 @@
   At the same time, management APIs for :ndn-cxx:`ValidatorConfig` remained intact;
   transition to the new framework only requires adjusting :ndn-cxx:`Validator::validate`
   calls and updating configuration files to follow the naming conventions of the new
-  `Certificate format <https://named-data.net/doc/NDN-packet-spec/0.3/certificate.html>`__.
+  `Certificate format <https://docs.named-data.net/NDN-packet-spec/0.3/certificate.html>`__.
 
 - Integration of fetching certificates using Certificate Bundle as part of specialized
   ``CertificateFetcher`` (:issue:`3891`)