This seems like you need to configure your CI tool to store the token as an environment variable, and then pull down that token each time you need to use it. This way you don’t persist the token to Github.
In terms of calling the collection with the environment, you should be able to do that with Postman API. Whatever you persist to Github will match what you already have.
You should be able to call the Postman API as well via newman.
Refer to the documentation below for how to use newman and Postman API.
If you would like a video to help explain, you can refer to these videos I made:
In your collection, you can persist the token as an environment variable in a test script (using the test script), and then from there, continue using the token as a variable.
I hope this helps!