Update release version to 8.4.0 and add issue link #5632

Job	Run time
build-and-test (stable)	56s
build-and-test (development-target)	54s
build-and-test (unstable)	1m 1s
lint	13s
open-suse-leap	2m 0s
fedora	1m 25s
	6m 29s

Provide feedback