Move CHANGELOG item to 7.13

CHANGELOG

 Please view this file on the master branch, on stable branches it's out of date.
 
+v 7.13.0 (unreleased)
+  - Rename "Design" profile settings page to "Preferences".
+  - Allow users to customize their default Dashboard page.
+
 v 7.12.0 (unreleased)
   - Update oauth button logos for Twitter and Google to recommended assets
   - Update browser gem to version 0.8.0 for IE11 support (Stan Hu)
@@ -54,8 +58,6 @@ v 7.12.0 (unreleased)
   - Improve group removing logic
   - Trigger create-hooks on backup restore task
   - Add option to automatically link omniauth and LDAP identities
-  - Rename "Design" profile settings page to "Preferences".
-  - Allow users to customize their default Dashboard page.
 
 v 7.11.4
   - Fix missing bullets when creating lists