feat(msk): add Kafka version 2.6.2 (#17497)

Add support for Apache Kafka version 2.6.2 in Amazon MSK.

Announcement: https://aws.amazon.com/about-aws/whats-new/2021/04/amazon-msk-adds-support-for-apache-kafka-version-2-6-2/

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*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: danielspang

packages/@aws-cdk/aws-msk/lib/cluster-version.ts

@@ -37,6 +37,11 @@ export class KafkaVersion {
    */
   public static readonly V2_6_1 = KafkaVersion.of('2.6.1');
 
+  /**
+   * Kafka version 2.6.2
+   */
+  public static readonly V2_6_2 = KafkaVersion.of('2.6.2');
+
   /**
    * Kafka version 2.7.0
    */