message: stargate: Add Cosmos SDK compatibility table
diff: A client library for the Cosmos SDK 0.40.
  +## Supported Cosmos-SDK versions
  +
  +| CosmJS version | Supported Cosmos SDK version(s) |
  +| -------------- | ------------------------------- |
  +| 0.24.0-alpha.2 | 0.40.0-rc2 |
  +| 0.24.0-alpha.1 | 0.40.0-rc1 |
  +
  ## License
  This package is part of the cosmjs repository, licensed under the Apache License
  