Update some default retry setting values (#4425)

Ref: https://github.com/googleapis/google-cloud-java/blob/ed7bc857a05b34eed6be182d4798a62bf09cd394/google-cloud-clients/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/Publisher.java#L497

google-cloud-examples/src/main/java/com/google/cloud/examples/pubsub/snippets/PublisherSnippets.java

@@ -113,12 +113,12 @@ public Publisher getPublisherWithCustomRetrySettings(ProjectTopicName topicName)
       throws Exception {
     // [START pubsub_publisher_retry_settings]
     // Retry settings control how the publisher handles retryable failures
-    Duration retryDelay = Duration.ofMillis(100); // default : 1 ms
-    double retryDelayMultiplier = 2.0; // back off for repeated failures
-    Duration maxRetryDelay = Duration.ofSeconds(5); // default : 10 seconds
-    Duration totalTimeout = Duration.ofSeconds(1); // default: 0
-    Duration initialRpcTimeout = Duration.ofSeconds(1); // default: 0
-    Duration maxRpcTimeout = Duration.ofSeconds(10); // default: 0
+    Duration retryDelay = Duration.ofMillis(5); // default: 5 ms
+    double retryDelayMultiplier = 2.0; // back off for repeated failures, default: 2.0
+    Duration maxRetryDelay = Duration.ofSeconds(600); // default : Long.MAX_VALUE
+    Duration totalTimeout = Duration.ofSeconds(10); // default: 10 seconds
+    Duration initialRpcTimeout = Duration.ofSeconds(10); // default: 10 seconds
+    Duration maxRpcTimeout = Duration.ofSeconds(10); // default: 10 seconds
 
     RetrySettings retrySettings =
         RetrySettings.newBuilder()