Update elasticsearch containers used in tests to 7.17.28 / 8.18.1

Change-Id: I40361d989df0d35622e0b2e97fe83624475406fa

src/test/java/com/google/gerrit/elasticsearch/ElasticContainer.java

diff --git a/src/test/java/com/google/gerrit/elasticsearch/ElasticContainer.java b/src/test/java/com/google/gerrit/elasticsearch/ElasticContainer.java
index 47e41af..e04eb89 100644
--- a/src/test/java/com/google/gerrit/elasticsearch/ElasticContainer.java
+++ b/src/test/java/com/google/gerrit/elasticsearch/ElasticContainer.java
@@ -91,9 +91,9 @@
     DockerImageName image = DockerImageName.parse("docker.elastic.co/elasticsearch/elasticsearch");
     switch (version) {
       case V7:
-        return image.withTag("7.17.24");
+        return image.withTag("7.17.28");
       case V8:
-        return image.withTag("8.15.2");
+        return image.withTag("8.18.1");
     }
     throw new IllegalStateException("No tests for version: " + version.name());
   }