Add latest changes from gitlab-org/gitlab@12-5-stable-ee

CHANGELOG-EE.md

 Please view this file on the master branch, on stable branches it's out of date.
+## 12.5.3
+
+### Performance (1 change)
+
+- Geo - Improve query performance to determine job artifacts to sync when selective sync is enabled. !19583
+
+### Other (1 change)
+
+- Geo - Does not schedule duplicated jobs while backfilling uploads, LFS objects and job artifacts. !20324
+
+
 ## 12.5.2
 - No changes.

VERSION

-12.5.3
+12.5.3-ee