private ConfigSource readYamlConfigFile(final Path path) throws IOException {
        return this.embed.newConfigLoader().fromYamlString(
                new String(Files.readAllBytes(path), StandardCharsets.UTF_8));
    }
Runs the run subcommand.

It receives a ConfigSource and a String as parameters to be called from Ruby (embulk/runner.rb).
embulk-core/src/main/java/org/embulk/EmbulkRunner.java