Based on Jonathan & Solomon work.
The only addition I've made is a Set node. This node organizes workflows into subfolders within the GitHub repository based on their respective tags.
This workflow will backup your workflows to GitHub. It uses the n8n API node to export all workflows.
It then loops over the data, checks in GitHub to see if a file exists that uses the credential's ID. Once checked it will:
People wanting to backup their workflows outside the server for safety purposes or to migrate to another server.