"narn outdated" fails with npm

In an npm project:

```sh
narn outdated
```

Results in:

```
npm run outdated
npm ERR! Missing script: "outdated"
npm ERR! 
npm ERR! Did you mean this?
npm ERR!     npm update # Update packages
npm ERR! 
npm ERR! To see a list of scripts, run:
npm ERR!   npm run
```

Since this is a special command, it cannot be run with `npm run` in npm.