add .netrc example to auth section

I had to search all around for this and I ended up finding it in component-dev... It would be nice if this was in the changelogs, as the error you receive in the console links to these changelogs.

`~/.netrc`
```
machine raw.github.com
  login visionmedia
  password pass123
```
line break to fix formatting, then i'll merge ;)