If you'd like to disconnect the GitHub integration, you can do so from your Team integrations page.
You need to be an admin on your GitHub account to disconnect your GitHub integration.
Step 1. Navigate to the GitHub Integration
Click on edit next to the integration:
You will be redirected to GitHub's Account settings (you will need to log in first). Scroll down and click Uninstall. If you're not already logged in to GitHub, you'll be directed to log in at this point.