Adjust 13.12.13 and 13.12.14 changelog entries

13.12.13 and 13.12.14 packages were skipped due to multiple QA issues
   that were fixed on 13.12.15. This commit updates the CHANGELOG.md
file to indicate this.

CHANGELOG.md

@@ -3066,18 +3066,18 @@ No changes.
 
 ## 13.12.15 (2021-11-03)
 
-No changes.
-
-## 13.12.14 (2021-11-03)
-
 ### Fixed (2 changes)
 
 - [Allow nil for remaining ci cd settings](gitlab-org/gitlab@896fd7ecf23714fa9f710efa4af245a26c677dce) ([merge request](gitlab-org/gitlab!73522))
 - [Allow nil on delegated CI/CD settings](gitlab-org/gitlab@d57a9ea79080fc473eb54c0ee696a50fd270e8a4) ([merge request](gitlab-org/gitlab!73522))
 
+## 13.12.14 (2021-11-03)
+
+This version has been skipped due to QA problems.
+
 ## 13.12.13 (2021-10-29)
 
-No changes.
+This version has been skipped due to QA problems.
 
 ## 13.12.12 (2021-09-21)