Update CHANGELOG.md for 8.15.8

[ci skip]

Former-commit-id: 4ccf874d

CHANGELOG.md

@@ -411,6 +411,11 @@ entry.
 - Add margin to markdown math blocks.
 - Add hover state to MR comment reply button.
+## 8.15.8 (2017-03-19)
+
+- Only show public emails in atom feeds.
+- To protect against Server-side Request Forgery project import URLs are now prohibited against localhost or the server IP except for the assigned instance URL and port. Imports are also prohibited from ports below 1024 with the exception of ports 22, 80, and 443.
+
 ## 8.15.7 (2017-02-15)
 - No changes.