Script within Workflow

Good morning,

I would like to run a script within a custom workflow. This script must be run as soon as the User Approve the task.
The idea I had so far was to create a custom property (flag) to a document and update its value to true when the dcumento is approved. And then create a folder rule that calls the script when this property(flag) is updated.
But I prefer this script to be executed within the workflow directly.
Does anyone have any idea / suggestion to help me?

The script is attached