code: @SuppressWarnings("unused")
    public static Builder fromDockerConfig(final String serverAddress) throws IOException {
      DockerConfigReader dockerCfgReader = new DockerConfigReader();
      return dockerCfgReader
          .authForRegistry(dockerCfgReader.defaultConfigPath(), serverAddress).toBuilder();
    }
docs: This function looks for and parses credentials for logging into the Docker registry specified
  by serverAddress. We first look in ~/.docker/config.json and fallback to ~/.dockercfg. These
  files are created from running `docker login`.
  
  @param serverAddress A string representing the server address
  @return a {@link Builder}
  @throws IOException when we can't parse the docker config file