Node module caching

Morning team. Firstly thanks for all your work on this, really appreciating the fixes. I do have a question about caching node modules. I've been using the `cache@v2` action for caching `./node_modules` using the lockfile as a key in my non-SWA based repos but it doesn't work here as it doesn't appear that the swa action copies `node_modules` into the Oryx workspace. As a result the npm dependencies have to be downloaded again.

I did wonder about copying them into the Oryx working dir using a custom build command but 1. that seems like a bit of a hack and 2. I'm not even sure that would work for projects with separate frontend and api lockfiles?

Is this a viable way of doing it or have I missed something?