Import manticore to resolve uninitialized Manticore error.

Author: mashhurs

CHANGELOG.md

@@ -1,5 +1,5 @@
 ## 5.0.2
-  - Adds elastic-transport support [#223](https://github.com/logstash-plugins/logstash-input-elasticsearch/pull/223)
+  - Add elastic-transport client support [#223](https://github.com/logstash-plugins/logstash-input-elasticsearch/pull/223)
 
 ## 5.0.1
   - Fix: prevent plugin crash when hits contain illegal structure [#218](https://github.com/logstash-plugins/logstash-input-elasticsearch/pull/218)

lib/logstash/inputs/elasticsearch.rb

@@ -13,6 +13,7 @@
 require "base64"
 
 require "elasticsearch"
+require "manticore"
 
 # .Compatibility Note
 # [NOTE]