Merge branch 'dev' into 'master'

<match **>

	@type elasticsearch_dynamic

	@id elasticsearch-output

	@log_level debug

	id_key _hash

	remove_keys _hash

	hosts "#{ENV['ES_HOSTS']}"

	logstash_format true

	logstash_prefix fluentd-${tag_parts[0]}

	logstash_dateformat %Y%m

	flush_interval 30s

	request_timeout 15s

	reconnect_on_error true

	reload_on_failure true

	reload_connections false

	<buffer>

		flush_mode interval

		flush_interval 30s

		flush_thread_count 4

	</buffer>

</match>