tidb: add a new entry in release notes 5.1.4 (#10266)

Author: hfxsd

releases/release-5.1.4.md

@@ -79,6 +79,7 @@ TiDB version: 5.1.4
     - Fix the `INDEX OUT OF RANGE` error for a MPP query after deleting an empty `dual table` [#28250](https://github.com/pingcap/tidb/issues/28250)
     - Fix the issue of false positive error log `invalid cop task execution summaries length` for MPP queries [#1791](https://github.com/pingcap/tics/issues/1791)
     - Fix the issue that SET GLOBAL tidb_skip_isolation_level_check=1 doesn't affect new session settings [#27897](https://github.com/pingcap/tidb/issues/27897)
+    - Fix the `index out of range` issue that occurs when `tiup bench` runs for a long time [#26832](https://github.com/pingcap/tidb/issues/26832)
 
 + TiKV