The correct option is a webhook.

A webhook is the mechanism GitHub Enterprise provides to send HTTP POST notifications to an external endpoint when repository events occur. You can configure a webhook to fire on the events that correspond to a rebase or to the push that follows a rebase and have your receiving service trigger the PowerShell script automatically based on the payload.

GitHub Copilot is a code suggestion and completion tool and it does not provide event notifications or a way to invoke scripts when repository operations happen.

Cloud Functions are a place to run code and they can host the receiver for events but they are not the GitHub-side mechanism that sends notifications. You would still rely on a webhook to notify a Cloud Functions endpoint.

Gist is a snippet and snippet sharing service and it does not offer an event notification mechanism to trigger scripts on repository actions.

Full AWS Practitioner Certification Question