feat(pkg-support): Add pkg entry to package.json

[bengreenier]

This allows pkg to include the static assets in the snapshot filesystem, addressing #28.

Checklist

• run npm run test and npm run benchmark (there is no benchmark script?)
• tests and/or benchmarks are included (don't feel these are relevant, omitting)
• documentation is changed or added (don't feel these are needed, omitting)
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[climba03003]

A bit late, but I don't think it is something that should be added.
You should probably file an issue to pkg.