Add changelog entry

Author: chipshort

CHANGELOG.md

@@ -10,9 +10,11 @@ and this project adheres to
 
 - cosmwasm-std: Add `SubMsg:reply_never` constructor ([#1929])
 - cosmwasm-std: Add optional memo field to `IbcMsg::Transfer`. ([#1878])
+- cosmwasm-std: Add `Reply::gas_used`. ([#1954])
 
 [#1878]: https://github.com/CosmWasm/cosmwasm/pull/1878
 [#1929]: https://github.com/CosmWasm/cosmwasm/pull/1929
+[#1954]: https://github.com/CosmWasm/cosmwasm/pull/1954
 
 ### Changed