Bump elasticsearch from 2.4.0 to 6.8.17 in /elasticsearch#21

dependabot[bot] wants to merge 1 commit intoproteusLightKone/ycsb:proteusfrom

dependabot/maven/elasticsearch/org.elasticsearch-elasticsearch-6.8.17LightKone/ycsb:dependabot/maven/elasticsearch/org.elasticsearch-elasticsearch-6.8.17Copy head branch name to clipboard