How can I get an AWS ECS TaskDefinition resource (https://www.pulumi.com/registry/packages/aws/api-docs/ecs/taskdefinition/#aws-ecs-taskdefinition) to

pulumi refresh

to the most recent active Task Definition Revision? By default, the resource refreshes to the TaskDefinition revision that Pulumi originally created, which isn't helpful when our pipelines have in the meantime created new revisions.

You cannot do this. When you change your TaskDefinition, do it via code change, not the console. This will ensure Pulumi remains the manager of all your resources.