message: Add SignerData to CHANGELOG
diff: @@ -39,7 +39,9 @@ and this project adheres to
  exports which have the same functionality as already existed in
  @cosmjs/launchpad.
  - @cosmjs/stargate: Add `SigningStargateClient.sign`, which allows you to create
  - signed transactions without broadcasting them directly.
  + signed transactions without broadcasting them directly. The new type
  + `SignerData` can be passed into `.sign` to skip querying account number,
  + sequence and chain ID.
  ### Changed
  