Move changelog items to their correct place.

CHANGELOG

@@ -4,12 +4,13 @@ v 8.4.0 (unreleased)
   - Fix Error 500 when doing a search in dashboard before visiting any project (Stan Hu)
   - Implement new UI for group page
   - Add project permissions to all project API endpoints (Stan Hu)
+  - Add CAS support (tduehr)
+  - Add link to merge request on build detail page.
+  - Expose Git's version in the admin area
 v 8.3.0
-  - Add CAS support (tduehr)
   - Bump rack-attack to 4.3.1 for security fix (Stan Hu)
   - API support for starred projects for authorized user (Zeger-Jan van de Weg)
-  - Add link to merge request on build detail page.
   - Add open_issues_count to project API (Stan Hu)
   - Expand character set of usernames created by Omniauth (Corey Hinshaw)
   - Add button to automatically merge a merge request when the build succeeds (Zeger-Jan van de Weg)
@@ -69,7 +70,6 @@ v 8.3.0
   - Do not show build status unless builds are enabled and `.gitlab-ci.yml` is present
   - Persist runners registration token in database
   - Fix online editor should not remove newlines at the end of the file
-  - Expose Git's version in the admin area
 v 8.2.3
   - Fix application settings cache not expiring after changes (Stan Hu)