Fix dev module name mask

When you try using the `dev` shortcut in `Puppetfile`, e.g.

```
github "gcc", "2.2.0"
dev "brewcask"
```
you'll see following warnings:
```
Invalid module name 'brewcask', you should qualify it with 'ORGANIZATION-brewcask' for resolution to work correctly
```

It's basically harmless, but annoying and this PR changes the name of the module from `modulename` to `puppet-modulename` -> therefore prevents these warnings.