[FLINK-7600] [kinesis] Shorten credential update delay to avoid updateCredentials Exception

The updateCredentials delay is an ignorable warning that occurs due to
the fact that the default credential update delay is longer than the
await termination timeout when shutting down KPL.

See https://github.com/awslabs/amazon-kinesis-producer/issues/10 for
details.

This closes #4657.

flink-connectors/flink-connector-kinesis/src/main/java/org/apache/flink/streaming/connectors/kinesis/util/KinesisConfigUtil.java

@@ -194,6 +194,11 @@ public class KinesisConfigUtil {
 
 		kpc.setCredentialsProvider(AWSUtil.getCredentialsProvider(config));
 
+		// we explicitly lower the credential refresh delay (default is 5 seconds)
+		// to avoid a ignorable interruption warning that occurs when shutting down the
+		// KPL client. See https://github.com/awslabs/amazon-kinesis-producer/issues/10.
+		kpc.setCredentialsRefreshDelay(100);
+
 		// Because of bug https://github.com/awslabs/amazon-kinesis-producer/issues/124
 		// KPL cannot set ThreadingModel and ThreadPoolSize using Java reflection
 		// Thus we have to set them explicitly