Merge remote-tracking branch 'engcom/1-es-6-dependencies' into 2.3.1-qwerty-pr

Author: Joan He

app/code/Magento/Elasticsearch/composer.json

@@ -12,7 +12,7 @@
         "magento/module-store": "*",
         "magento/module-catalog-inventory": "*",
         "magento/framework": "*",
-        "elasticsearch/elasticsearch": "~2.0|~5.1"
+        "elasticsearch/elasticsearch": "~2.0|~5.1|~6.1"
     },
     "suggest": {
         "magento/module-config": "*"

app/code/Magento/Elasticsearch6/composer.json

@@ -9,7 +9,7 @@
         "magento/module-search": "*",
         "magento/module-store": "*",
         "magento/module-elasticsearch": "*",
-        "elasticsearch/elasticsearch": "~6.1"
+        "elasticsearch/elasticsearch": "~2.0|~5.1|~6.1"
     },
     "suggest": {
         "magento/module-config": "*"