Update 4.0.0 release notes

(cherry picked from commit c66e5ea)

# Conflicts:
#	release-notes/4.0.0.md

Author: michaelklishin

release-notes/4.0.0.md

@@ -88,5 +88,9 @@ TBD
 
 ## Source Code Archives
 
+<<<<<<< HEAD
 To obtain source code of the entire distribution, please download the archive named `rabbitmq-server-4.0.0-beta.1.tar.xz`
+=======
+To obtain source code of the entire distribution, please download the archive named `rabbitmq-server-3.13.4.tar.xz`
+>>>>>>> c66e5ea058 (Update 4.0.0 release notes)
 instead of the source tarball produced by GitHub.