For my google cloud project I want to update ONLY my app.yaml file, I do not want to deploy all of the files in my project. Can I just run gcloud app deploy app.yaml? I'm worried it will deploy all of my files and I'm not in a good position to do that at the moment. I can't find documentation that assures me this is what I want.
UPDATE: What I actually want is to be able to update my instance_class & automatic_scaling params without deploying my project.
Donnald C pointed me in the right direction and I found documentation with an online API Explorer that helps you setup and execute a patch to your config.
https://cloud.google.com/appengine/docs/standard/php/config/setting-autoscaling-params-in-explorer