Changelog:
* Upgraded CDK version to support EFS usage
* Upgraded Fargate PlatformVersion to support EFS mounts
* Refacored RDS contruct as per new CDK
* Created a new LogGroup for OnDemand DagTasks
* Added TAG for stack, to track resources belonging to this setup
* Updated sample DAG to utilize EFS. Tasks Odd and Even will publish to EFS and Numbers will read from EFS
* Now you can see logs from OnDemand tasks on Airflow UI, once task run finishes
