Update Nodejs App launched with Pm2 as Windows Service

Question

I'm writing an small application in nodejs.

This app should be executed as windows service (so I can't use electron or others because It should be active even if the user is not logged), and so I have thought to use PM2. It starts and works fine, but my problem, now, are the updates of my NodeJS app.

My app will released to many PC and I don't want update it one by one.

Yes, I have a repository where I can read and so I can create in my app a function where with established interval I go to my repo and pull.

For now I have created, in packages.json of my NodeJs app a scripts command like:

git pull //myrepourl.git origin

And in my index.js a function like:

function updateApp(){
    return new Promise((resolve,reject)=>{
        exec('cd app_path && npm run prod_update', (error, stdout, stderr) => {
            if (error) {
                console.error(`exec error: ${error}`);
                reject();
            }
            resolve();
        });
    })

}
setInterval( ()=>{
        updateApp();
        console.log("------ Updated ---------")

    },60*60*1000);

But this way don't convince me because actually my repo is private and then I have to expose my credentials git in app, whithout considering the problem of node_modules.

So are there others way to update a Nodejs app launched with PM2 as Service on Windows?