K-9 email - update Changelog link

metadata/com.fsck.k9.txt

@@ -4,7 +4,7 @@ License:Apache-2.0
 Web Site:https://k9mail.github.io/
 Source Code:https://github.com/k9mail/k-9
 Issue Tracker:https://github.com/k9mail/k-9/issues
-Changelog:https://github.com/k9mail/k-9/wiki/ReleaseNotes
+Changelog:https://k9mail.github.io/k-9/changelog_5.6-MAINT_branch.xml
 LiberapayID:34990
 
 Auto Name:K-9 Mail