You should review deploy keys to ensure that there aren't any unauthorized (or possibly compromised) keys. You can also approve existing deploy keys that are valid.
On GitHub, navigate to the main page of the repository.
Under your repository name, click Settings.
In the left sidebar, click Deploy keys.
- On the Deploy keys page, take note of the deploy keys associated with your account. For those that you don't recognize, or that are out-of-date, click Delete. If there are valid deploy keys you'd like to keep, click Approve.
For more information, see "Managing deploy keys" in the GitHub Developer documentation.