Update CHANGELOG.md

Signed-off-by: mmsqe <mavis@crypto.com>

Author: mmsqe

CHANGELOG.md

@@ -4,7 +4,7 @@
 
 ### Improvements
 
-- [#](https://github.com/crypto-org-chain/cronos/pull/) Add packet_sequence index in relayer event.
+- [#1318](https://github.com/crypto-org-chain/cronos/pull/1318) Add packet_sequence index in relayer event.
 
 *February 5, 2024*