I have a private package that I need to bundle into my webapp to deploy on Vercel. It contains a Node addon (.node), a few libraries (.so), and a wrapper interface (index.js). However, when Vercel deploys, the directory that it places my module into (/var/tasks/packages/mymodule) ONLY contains index.js and package.json, and none of the other required files, which live in './lib/' relative to index.js. How can I fix this?