Update CHANGELOG.md for 9.0.8

[ci skip]

CHANGELOG.md

@@ -523,6 +523,12 @@ entry.
 - Only send chat notifications for the default branch.
 - Don't fill in the default kubernetes namespace.
 
+## 9.0.8 (2017-05-31)
+
+- Move uploads from 'public/uploads' to 'public/uploads/system'.
+- Restrict API X-Frame-Options to same origin.
+- Allow users autocomplete by author_id only for authenticated users.
+
 ## 9.0.7 (2017-05-05)
 
 - Enforce project features when searching blobs and wikis.