adds entry in CHANGELOG

CHANGELOG.md

@@ -10,7 +10,7 @@ Please view this file on the master branch, on stable branches it's out of date.
   - Use MergeRequestsClosingIssues cache data on Issue#closed_by_merge_requests method
 
 ## 8.13.0 (2016-10-22)
-
+  - Removes extra line for empty issue description. (!7045)
   - Fix save button on project pipeline settings page. (!6955)
   - Avoid race condition when asynchronously removing expired artifacts. (!6881)
   - Improve Merge When Build Succeeds triggers and execute on pipeline success. (!6675)