message: Update CHANGELOG for SigningCosmWasmClient.offline
diff: @@ -53,6 +53,8 @@ and this project adheres to
  - @cosmjs/stargate: `SigningStargateClient` constructor is now `protected`.
  - @cosmjs/cosmwasm-stargate: `SigningCosmWasmClient` constructor is now
  `protected`.
  +- @cosmjs/cosmwasm-stargate: Add `SigningCosmWasmClient.offline` static method
  + for constructing offline clients without a Tendermint client.
  ### Changed
  