Use new template API on out_elasticsearch_data_stream
Use new template API on out_elasticsearch_data_stream

Data stream API supported Elasticsearch always supports new composable
index template API. We should use new API by default.

Signed-off-by: Hiroshi Hatake <54b742842f0d940c9715551f77be1b560ea6cc67@gmail.com>

uken/fluent-plugin-elasticsearch