Otherwise, this generator creates a Go file with some import statements,
that causes "imported and not used" error.
Signed-off-by: Kazuyoshi Kato <katokazu@amazon.com>
Google's new protobuf code generator only supports protobuf
serialization/deserialization and let other code generators handle
RPC-related aspects.
This new code generator follows the change and can be used with
the new protobuf code generator.
Signed-off-by: Kazuyoshi Kato <katokazu@amazon.com>
