Add latest changes from gitlab-org/security/gitlab@12-6-stable-ee

CHANGELOG-EE.md

 Please view this file on the master branch, on stable branches it's out of date.
+## 12.6.7
+
+- No changes.
+
 ## 12.6.6
 - No changes.

VERSION

-12.6.7
+12.6.7-ee