AWS::AmazonMQ::Broker.EngineVersion AllowedValues expansion (5.15.14) (…

…aws-cloudformation#1841)

aws-cloudformation#50
one of the few AllowedValues lists left to actively maintain:
aws-cloudformation#1682
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-amazonmq-broker.html#cfn-amazonmq-broker-engineversion
https://docs.aws.amazon.com/amazon-mq/latest/developer-guide/broker-engine.html

src/cfnlint/data/ExtendedSpecs/all/03_value_types/aws_amazonmq.json

@@ -25,7 +25,8 @@
         "5.15.9",
         "5.15.10",
         "5.15.12",
-        "5.15.13"
+        "5.15.13",
+        "5.15.14"
       ]
     }
   },