update changelog

Author: JayT106

CHANGELOG.md

@@ -135,6 +135,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (sdk/dec_coins) [#12903](https://github.com/cosmos/cosmos-sdk/pull/12903) Fix nil `DecCoin` creation when converting `Coins` to `DecCoins`
 * (x/upgrade) [#12906](https://github.com/cosmos/cosmos-sdk/pull/12906) Fix upgrade failure by moving downgrade verification logic after store migration.
 * (store) [#12945](https://github.com/cosmos/cosmos-sdk/pull/12945) Fix nil end semantics in store/cachekv/iterator when iterating a dirty cache.
+* (export) [#13029](https://github.com/cosmos/cosmos-sdk/pull/13029) Fix exporting the blockParams regression.
 
 ### Deprecated