The `NpmPackageId` struct is being renamed to `NpmPackageNodeId`. In a
future PR it will be moved down into only npm dependency resolution and
a `NpmPackageId` struct will be introduced in `deno_graph` that only has
the name and version of the package (no peer dependency identifier
information). So a `NpmPackageReq` will map to an `NpmPackageId`, which
will map to an `NpmPackageNodeId` in the npm resolution.