Update CHANGELOG.md for 13.8.8-ee

[ci skip]

CHANGELOG.md

@@ -1199,6 +1199,14 @@ entry.
 - Apply new GitLab UI for buttons in pipeline schedules.
+## 13.8.8 (2021-04-13)
+
+### Security (2 changes)
+
+- Clean only legitimate JPG and TIFF files.
+- Update ruby-saml and rexml gems.
+
+
 ## 13.8.7 (2021-03-31)
 ### Security (5 changes)

changelogs/unreleased/security-327154-only-jpeg-tiff.yml

----
-title: Clean only legitimate JPG and TIFF files
-merge_request:
-author:
-type: security

changelogs/unreleased/security-ruby-saml-auth-bypass-fix.yml

----
-title: Update ruby-saml and rexml gems
-merge_request:
-author:
-type: security