riak-protobuf-0.24.0.0: Changes.md

* 0.24.0.0
 - Regenerate protobuf for protocol-buffers 2.4.12. (https://github.com/riak-haskell-client/riak-haskell-client/issues/115)
* 0.22.0.0
  - Support for riak 2.* messages
  - No longer expected to work with riak <= 2
  - Tested on both 2.0.x and 2.1.x