use elasticsearch 7.x in CI

.github/workflows/reusable-app-prod.yml

@@ -96,7 +96,7 @@ jobs:
         ports:
         - 27017/tcp
       elasticsearch:
-        image: docker.elastic.co/elasticsearch/elasticsearch:6.8.23
+        image: docker.elastic.co/elasticsearch/elasticsearch:7.17.1
         ports:
         - 9200/tcp
         env:
@@ -193,7 +193,7 @@ jobs:
         ports:
         - 27017/tcp
       elasticsearch:
-        image: docker.elastic.co/elasticsearch/elasticsearch:6.8.23
+        image: docker.elastic.co/elasticsearch/elasticsearch:7.17.1
         ports:
         - 9200/tcp
         env: