message: Update CHANGELOG for ledger-amino renaming
diff: - @cosmjs/launchpad: Add support for undefined memo in `makeSignDoc`.
  - @cosmjs/launchpad: Rename `SigningCosmosClient.senderAddress` to
  `.signerAddress`.
  -- @cosmjs/launchpad-ledger: `LedgerSigner.sign` method renamed `signAmino`.
  - @cosmjs/proto-signing: Add new package for handling transaction signing with
  protobuf encoding.
  - @cosmjs/proto-signing: Expose `DirectSignResponse` interface.
  - @cosmjs/utils: Added `assertDefinedAndNotNull`.
  +### Changed
  +
  +- @cosmjs/launchpad-ledger: Renamed to @cosmjs/ledger-amino.
  +- @cosmjs/ledger-amino: `LedgerSigner.sign` method renamed `signAmino`.
  +
  ## 0.23.2 (2021-01-06)
  ### Security
  