Elasticsearch: Discontinue EOL versions 7.2 and 7.3 support

Remove support for elasticsearch versions 7.2 and 7.3, as both became
EOL recently [1].

[1] https://www.elastic.co/support/eol

Change-Id: Ib48900ce4c5530023a5425d1fe3e65e03f17c933
3 files changed
tree: decc9e995f1650f9b99ea1b991b37c9bc8fd3250
  1. java/
  2. javatests/