Add support for Elasticsearch version 7.8.*

Upgrade elasticsearch-rest-client to 7.8.0.

Add V7_8 to the version manager and use it for all the V7 tests.

Change-Id: I1474289bd5636ab30dcff6b14e78feddc3e8be60
9 files changed
tree: f8d12dd65e3390217d8fccce734967c3f169fcbb
  1. java/
  2. javatests/