Update CHANGELOG.md for 11.9.10

[ci skip]

CHANGELOG.md

@@ -263,6 +263,17 @@ entry.
 - Removes EE differences for environment_item.vue.
 
 
+## 11.9.10 (2019-04-26)
+
+### Security (5 changes)
+
+- Loosen regex for exception sanitization. !3077
+- Resolve: moving an issue to private repo leaks namespace and project name.
+- Escape path in new merge request mail.
+- Stop sending emails to users who can't read commit.
+- Upgrade Rails to 5.0.7.2.
+
+
 ## 11.9.9 (2019-04-23)
 
 ### Performance (1 change)