Support an option for arbitrary trackingId?

[tomitamasa]

Hello, I'm currently using ecschedule in a project. The tool you made is super helpful!!

We have a problem when trying to use the -prune option in our project.
Our project has multiple YAML files for the same environment, and when we execute a command with the -prune option, settings from the last apply YAML file overwrite the others.

I am hoping to be able to specify an arbitrary trackingId.
like ↓

region: us-east-1
cluster: clusterName
trackingId: group-1
rules:
- name: taskName1
  description: task 1

If no options are specified,I think it should default to the value base.Cluster.

This feature would significantly enhance the usability of ecschedule in complex environments with multiple configuration files.

May I attempt to implement this?
Just to note, I am a beginner in Go.