4.0.4 release notes: correct a link

(cherry picked from commit 3a5d057)

Author: michaelklishin

release-notes/4.0.4.md

@@ -208,7 +208,7 @@ Release notes can be found on GitHub at [rabbitmq-server/release-notes](https://
 
 ### Dependency Changes
 
-  * `osiris` was upgraded to [`1.8.4`](https://github.com/rabbitmq/osiris)
+  * `osiris` was upgraded to [`1.8.4`](https://github.com/rabbitmq/osiris/releases/)
 
 
 ## Source Code Archives