Merge branch 'stable-2.15' into stable-2.16

* stable-2.15:
  Synchronize protobuf with version used in rules_closure
  Update rules_closure to latest version
  Upgrade elasticsearch-rest-client to 7.1.1

Change-Id: If4cdcc44c53e90f3562bdff1b7a30dd09cd9764f
tree: 5188d587b728ac02a3137bfc427a2e8b963fcff4
  1. java/
  2. javatests/