@Override
  public void close() throws IOException {
    if (shutDownExecutorService) {
      executorService.shutdown();
    }
    httpClient.shutDown();
  }
Creates a new {@link com.google.cloud.tools.jib.registry.RegistryClient.Factory} for the target
image with fields from the build configuration.

@return a new {@link com.google.cloud.tools.jib.registry.RegistryClient.Factory}
jib-core/src/main/java/com/google/cloud/tools/jib/configuration/BuildContext.java