Update CHANGELOG.md for 12.1.5

[ci skip]

CHANGELOG.md

@@ -2,6 +2,14 @@
 documentation](doc/development/changelog.md) for instructions on adding your own
 entry.
+## 12.1.5
+
+### Security (2 changes)
+
+- Upgrade Gitaly to 1.53.2 to prevent revision flag injection exploits.
+- Upgrade pages to 1.7.1 to prevent gitlab api token recovery from cookie.
+
+
 ## 12.1.4
 ### Fixed (3 changes, 1 of them is from the community)

changelogs/unreleased/fix-gitaly-revision-flag-injection.yml

----
-title: Upgrade Gitaly to 1.53.2 to prevent revision flag injection exploits
-merge_request:
-author:
-type: security

changelogs/unreleased/security-pages-api-token-recovery.yml

----
-title: Upgrade pages to 1.7.1 to prevent gitlab api token recovery from cookie
-merge_request:
-author:
-type: security