How to deploy using CD workflows (using GitHub) without putting secrets like API tokens on GitHub?

I am doing a project for my university class, so my repo has to be public in order for the lecturer to view my code. But I also have to deploy using Git, because it is part of the project.

I am using 3 API's and I normally hard code the tokens, but have now switched to reading them from files, and excluding the files in the .gitignore. The thing is, if I ignore these files it won't get deployed to the cloud, since I deploy with git.

I know there must be a solution, but I couldn't find anything online. Any help would be appreciated!