Update CHANGELOG

CHANGELOG

@@ -7,6 +7,11 @@ v 5.4.0
   - Misspelling fixes
   - Added support of unicorn and fog gems
   - Added client list to API doc
+  - Fix PostgreSQL database restoration problem
+  - Increase snippet content column size
+  - allow project import via git:// url
+  - Show participants on issues, including mentions
+  - Notify mentioned users with email
 v 5.3.0
   - Refactored services