ElasticContainer: Upgrade V7_7 to elasticsearch 7.7.1

Change-Id: Ibad2867e70d9ae960428bed7c127bc35f93b73b5
diff --git a/javatests/com/google/gerrit/elasticsearch/ElasticContainer.java b/javatests/com/google/gerrit/elasticsearch/ElasticContainer.java
index 15094fd..e436db5 100644
--- a/javatests/com/google/gerrit/elasticsearch/ElasticContainer.java
+++ b/javatests/com/google/gerrit/elasticsearch/ElasticContainer.java
@@ -59,7 +59,7 @@
       case V7_6:
         return "blacktop/elasticsearch:7.6.2";
       case V7_7:
-        return "blacktop/elasticsearch:7.7.0";
+        return "blacktop/elasticsearch:7.7.1";
     }
     throw new IllegalStateException("No tests for version: " + version.name());
   }