Update HISTORY.md for PR7329 (#7355)

Summary:
As title.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7355

Reviewed By: pdillinger

Differential Revision: D23566635

Pulled By: riversand963

fbshipit-source-id: f8d846bcff637e7617b764b7bfb9a948ea18d195

HISTORY.md

@@ -24,6 +24,7 @@
 * Expose kTypeDeleteWithTimestamp in EntryType and update GetEntryType() accordingly.
 * Added file_checksum and file_checksum_func_name to TableFileCreationInfo, which can pass the table file checksum information through the OnTableFileCreated callback during flush and compaction.
 * A warning is added to `DB::DeleteFile()` API describing its known problems and deprecation plan.
+* Add a new stats level, i.e. StatsLevel::kExceptTickers (PR7329) to exclude tickers even if application passes a non-null Statistics object.
 
 ### Behavior Changes
 * File abstraction `FSRandomAccessFile.Prefetch()` default return status is changed from `OK` to `NotSupported`. If the user inherited file doesn't implement prefetch, RocksDB will create internal prefetch buffer to improve read performance.