add to changlog

CHANGELOG.md

@@ -25,16 +25,21 @@ and this project adheres to
 - cosmwasm-std: Implement `AsRef<[u8]>` for `Binary` and `HexBinary` ([#1550]).
 - cosmwasm-std: Allow constructing `SupplyResponse` via a `Default`
   implementation ([#1552], [#1560]).
+- cosmwasm-std: Implement fraction multiplication and division. Assists with
+  Uint & Decimal arithmetic and exposes methods for flooring/ceiling result
+  ([#1485], [#1566]).
 
 [#1436]: https://github.com/CosmWasm/cosmwasm/issues/1436
 [#1437]: https://github.com/CosmWasm/cosmwasm/issues/1437
 [#1481]: https://github.com/CosmWasm/cosmwasm/pull/1481
+[#1485]: https://github.com/CosmWasm/cosmwasm/issues/1485
 [#1478]: https://github.com/CosmWasm/cosmwasm/pull/1478
 [#1533]: https://github.com/CosmWasm/cosmwasm/pull/1533
 [#1550]: https://github.com/CosmWasm/cosmwasm/issues/1550
 [#1552]: https://github.com/CosmWasm/cosmwasm/pull/1552
 [#1554]: https://github.com/CosmWasm/cosmwasm/pull/1554
 [#1560]: https://github.com/CosmWasm/cosmwasm/pull/1560
+[#1566]: https://github.com/CosmWasm/cosmwasm/pull/1566
 
 ### Changed