Merge branch 'stable-3.2'

* stable-3.2:
  Update git submodules
  Fix documentation of `container.slave`
  Fix documentation of `container.slave`
  Update git submodules
  Update git submodules
  Submit: Use updated change for response
  Remove Content-Type header from 'Submit Revision' example
  Update git submodules
  Add support for Elasticsearch version 7.8.*
  Fix `parent` in `gr-change-metadata` when there is no revision

Change-Id: Ifaaad90a7343da4e301137616bc7c82e92bd6f3c
tree: 66aa7d5799fc1d565e40a746cbadcb864250f42b
  1. java/
  2. javatests/