Update CHANGELOG.md

Signed-off-by: yihuang <huang@crypto.com>

Author: yihuang

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ## UNRELEASED
 
-- [#]() Support hard-fork style upgrades.
+- [#1258](https://github.com/crypto-org-chain/cronos/pull/1258) Support hard-fork style upgrades.
 
 *December 11, 2023*