Update to 7.3.1

* [Elasticsearch 7.3.1 Release Notes](https://www.elastic.co/guide/en/elasticsearch/reference/current/release-notes-7.3.1.html)
* [Kibana 7.3.1 Release Notes](https://www.elastic.co/guide/en/kibana/current/release-notes-7.3.1.html)
* [Logstash 7.3.1 Release Notes](https://www.elastic.co/guide/en/logstash/current/logstash-7-3-1.html)