message: Update README.md
  if we run original command, it makes error below
  ERROR: .FileNotFoundError: [Errno 2] No such file or directory: './docker-compose-dawn3.0.yml'
  After I changed .yml to .yaml, it works
  I think this maybe typo.
  Thanks
diff: @@ -160,7 +160,7 @@ docker pull eosio/eos:dawn3x
  docker volume create --name=nodeos-data-volume
  docker volume create --name=keosd-data-volume
  # start containers
  -docker-compose -f docker-compose-dawn3.0.yml up -d
  +docker-compose -f docker-compose-dawn3.0.yaml up -d
  # get chain info
  curl http://127.0.0.1:8888/v1/chain/get_info
  # get logs
  