Update CHANGELOG.md for 11.8.9

[ci skip]

CHANGELOG.md

@@ -2,6 +2,17 @@
 documentation](doc/development/changelog.md) for instructions on adding your own
 entry.
+## 11.8.9 (2019-04-25)
+
+### Security (5 changes)
+
+- Improve credentials sanitization on repository mirror integration. !3078
+- Stop sending emails to users who can't read commit.
+- Escape path in new merge request mail.
+- Only allow modification of content when note is edited.
+- Upgrade Rails to 5.0.7.2.
+
+
 ## 11.8.8 (2019-04-23)
 ### Fixed (5 changes)

changelogs/unreleased/security-57153-comments-on-confidential-issues.yml

----
-title: Only allow modification of content when note is edited
-merge_request:
-author:
-type: security

changelogs/unreleased/security-id-email-xss.yml

----
-title: Escape path in new merge request mail
-merge_request:
-author:
-type: security

changelogs/unreleased/security-pb-email-watchers-no-access.yml

----
-title: Stop sending emails to users who can't read commit
-merge_request:
-author:
-type: security

changelogs/unreleased/security-update-gitaly-to-11-20-1.yml

----
-title: Improve credentials sanitization on repository mirror integration
-merge_request: 3078
-author:
-type: security

changelogs/unreleased/security-upgrade-to-rails-5-0-7-2.yml

----
-title: Upgrade Rails to 5.0.7.2
-merge_request:
-author:
-type: security