Then you can skip all the CI/CD stuff (it's overkill for something like this) and just send a plain fetch from your app's backend (NOT the frontend/client!! Don't expose your Github tokens to your users!). You can either use their JS SDK or just send the raw HTTP commands.
Because you're on Github and wanting to edit it from another cloud app, it might be easier to just use the Github API (which is its own thing, not git-based) to edit the file directly: https://docs.github.com/en/rest/repos/contents?apiVersion=20...
Then you can skip all the CI/CD stuff (it's overkill for something like this) and just send a plain fetch from your app's backend (NOT the frontend/client!! Don't expose your Github tokens to your users!). You can either use their JS SDK or just send the raw HTTP commands.