[`libnpmpack`](https://github.com/npm/libnpmpack) is a Node.js library for
programmatically packing tarballs from a local directory or from a registry or github spec. If packing from a local source, `libnpmpack` will also run the `prepack` and `postpack` lifecycles.
Packs a tarball from a local directory or from a registry or github spec and returns a Promise that resolves to the tarball data Buffer, with from, resolved, and integrity fields attached.
If no options are passed, the tarball file will be saved on the same directory from which `pack` was called in.