After a GitHub access token is created/rotated a CircleCI Environment Variable may need to be updated using the following steps:
CircleCI > Project Settings > Environment Variables > Add Environment Variable
The COMPOSER_AUTH
name is picked up automatically - if there's an existing one just click the "Add Enviornment Variable" button with the same name to replace.
Value format (replace with your token value):
{"github-oauth": {"github.com": "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"}}