ElasticContainer: Update the 6.6 version to latest

There are no concerning breaking changes since the previously used
version, according to the release notes [1].

Also update the elasticsearch-rest-client version accordingly, for which
the httpasyncclient and httpcore-nio explicit dependencies didn't change
(versions in [2]).

[1] https://www.elastic.co/guide/en/elasticsearch/reference/current/release-notes-6.6.2.html
[2] https://search.maven.org/artifact/org.elasticsearch.client/elasticsearch-rest-client/6.6.2/jar

Change-Id: I584af10003b4765e0b8b08aea8b2852d5616dc9f
diff --git a/WORKSPACE b/WORKSPACE
index dbdd442..a180f58 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -896,8 +896,8 @@
 # and httpasyncclient as necessary.
 maven_jar(
     name = "elasticsearch-rest-client",
-    artifact = "org.elasticsearch.client:elasticsearch-rest-client:6.6.1",
-    sha1 = "dc1c9284ffca28cd169fae2776c3956e90b76c00",
+    artifact = "org.elasticsearch.client:elasticsearch-rest-client:6.6.2",
+    sha1 = "2c429141e488091c358aa43b1e6873d457464c5d",
 )
 
 JACKSON_VERSION = "2.9.8"
diff --git a/gerrit-elasticsearch/src/test/java/com/google/gerrit/elasticsearch/ElasticContainer.java b/gerrit-elasticsearch/src/test/java/com/google/gerrit/elasticsearch/ElasticContainer.java
index 1c7102a..30c7141 100644
--- a/gerrit-elasticsearch/src/test/java/com/google/gerrit/elasticsearch/ElasticContainer.java
+++ b/gerrit-elasticsearch/src/test/java/com/google/gerrit/elasticsearch/ElasticContainer.java
@@ -47,7 +47,7 @@
       case V6_5:
         return "docker.elastic.co/elasticsearch/elasticsearch-oss:6.5.4";
       case V6_6:
-        return "docker.elastic.co/elasticsearch/elasticsearch-oss:6.6.1";
+        return "docker.elastic.co/elasticsearch/elasticsearch-oss:6.6.2";
       case V7_0:
         return "docker.elastic.co/elasticsearch/elasticsearch-oss:7.0.0-beta1";
     }