Add Changelog entry.

CHANGELOG

@@ -36,6 +36,7 @@ v 8.9.0 (unreleased)
   - Improve error handling importing projects
   - Put project Files and Commits tabs under Code tab
   - Replace Colorize with Rainbow for coloring console output in Rake tasks.
+  - An indicator is now displayed at the top of the comment field for confidential issues.
 v 8.8.4
   - Fix todos page throwing errors when you have a project pending deletion