ElasticContainer: Upgrade V7_6 to elasticsearch 7.6.2

Upgrade elasticsearch-rest-client to 7.6.2, accordingly.

Change-Id: If7d3795a4b4cb352d3c57dc83077f58c7032defc
1 file changed
tree: b1fa470b772a44a3dfd6a605d91e398a670d3f4d
  1. java/
  2. javatests/