Update CHANGELOG.md for 13.8.7-ee

[ci skip]

CHANGELOG.md

@@ -2,6 +2,27 @@
 documentation](doc/development/changelog.md) for instructions on adding your own
 entry.
+## 13.8.7 (2021-03-31)
+
+### Security (5 changes)
+
+- Fixed XSS in merge requests sidebar.
+- Leave pool repository on fork unlinking.
+- Fix arbitrary read/write in AsciiDoctor and Kroki gems.
+- Prevent infinite loop when checking if collaboration is allowed.
+- Require POST request to trigger system hooks.
+
+### Removed (1 change)
+
+- Make HipChat project service do nothing. !57434
+
+### Other (3 changes)
+
+- Remove direct mimemagic dependency. !57387
+- Refactor MimeMagic calls to new MimeType class. !57421
+- Switch to using a fake mimemagic gem. !57443
+
+
 ## 13.8.6 (2021-03-17)
 ### Security (1 change)

changelogs/unreleased/mimemagic_shim.yml

----
-title: Switch to using a fake mimemagic gem
-merge_request: 57443
-author:
-type: other

changelogs/unreleased/remove-direct-mimemagic-dependency-minimal.yml

----
-title: Refactor MimeMagic calls to new MimeType class
-merge_request: 57421
-author:
-type: other

changelogs/unreleased/remove-direct-mimemagic-dependency.yml

----
-title: Remove direct mimemagic dependency
-merge_request: 57387
-author:
-type: other

changelogs/unreleased/remove_hipchat_gem.yml

----
-title: Make HipChat project service do nothing
-merge_request: 57434
-author:
-type: removed

changelogs/unreleased/security-fix-xss-in-mr-sidebar.yml

----
-title: Fixed XSS in merge requests sidebar
-merge_request:
-author:
-type: security

changelogs/unreleased/security-id-leave-pool-for-private-forks.yml

----
-title: Leave pool repository on fork unlinking
-merge_request:
-author:
-type: security

changelogs/unreleased/security-kroki-arbitraryfile-read-write.yml

----
-title: Fix arbitrary read/write in AsciiDoctor and Kroki gems
-merge_request:
-author:
-type: security

changelogs/unreleased/security-projects-branch-collaboration-loop.yml

----
-title: Prevent infinite loop when checking if collaboration is allowed
-merge_request:
-author:
-type: security

changelogs/unreleased/security-trigger-system-hook-by-post.yml

----
-title: Require POST request to trigger system hooks
-merge_request:
-author:
-type: security