Update CHANGELOG.md for 11.2.5

[ci skip]

CHANGELOG.md

@@ -279,6 +279,15 @@ entry.
 - Creates Vue component for artifacts block on job page.
 
 
+## 11.2.5 (2018-10-05)
+
+### Security (3 changes)
+
+- Filter user sensitive data from discussions JSON. !2538
+- Properly filter private references from system notes.
+- Markdown API no longer displays confidential title references unless authorized.
+
+
 ## 11.2.4 (2018-09-26)
 
 ### Security (6 changes)