Update package.json
Update package.json

Leave `os` and `cpu` out since they're empty anyway. This is throwing an error with yarn.

```
error feed@0.3.0: The platform "darwin" is incompatible with this module.
error feed@0.3.0: The CPU architecture "x64" is incompatible with this module.
error Found incompatible module
```
jpmonette/feed,jpmonette/feed