message: Update CHANGELOG for getSequence changes
diff: @@ -87,6 +87,10 @@ and this project adheres to
  query and `CosmWasmClient.getAccountUnverified` has been removed.
  `CosmWasmClient.getAccountVerified` has been added, which performs a verified
  query.
  +- @cosmjs/stargate: `StargateClient.getSequence` now rejects if the account is
  + not found, instead of returning null.
  +- @cosmjs/cosmwasm-stargate: `CosmWasmClient.getSequence` now rejects if the
  + account is not found, instead of returning null.
  ### Deprecated
  