ECS role managed policy AmazonEC2RoleforSSM soon to be deprecated

[tfentonz]

The ECS Cluster ECS role has managed policy AmazonEC2RoleforSSM attached.

In IAM this policy has the following description:

This policy will soon be deprecated. Please use AmazonSSMManagedInstanceCore policy to enable AWS Systems Manager service core functionality on EC2 instances. For more information see https://docs.aws.amazon.com/systems-manager/latest/userguide/setup-instance-profile.html

Update the ECS Role to use the suggested AmazonSSMManagedInstanceCore policy.