Merge branch 'stable-2.16' into stable-3.0
* stable-2.16:
Error Prone: Fix DefaultCharset in ListProjectsIT
Bazel: Enable Error-Prone by default
Parallelize account migration in schema 146 migration
Fix _nextStepHandle not being assigned a value when scrolling
Elasticsearch: Remove redundant handling of 'ignore_unmapped' property
Elasticsearch: Fix support for V6 versions earlier than 6.7.*
Clarify introduction to external IDs
ExternalIdNotes: Improve grammar in checkState messages
Update git submodules
Add example of external ID key in external ID documentation
Minor grammatical fixes in external ID documentation
ElasticVersionTest: Add missing assertions on V6_7
Also update the replication plugin revision to include the fix:
HttpResponse: Specify charset in constructor of InputStreamReader
which is needed due to enabling error prone checks on core plugins.
Change-Id: I90394f5c0d6aaf88b1169c26ceb65b699fddfe77
