Pass name to custom driver

[tomhelmer]

When creating a custom driver the name from the config is not passed.

In my case I'm extending with a custom search driver, but the index name public is currently not available in the custom creator callback. So the custom driver don't know how to name the index.

This PR passes the config name as a third parameter to the custom creator callback.

Example config:

'indexes' => [
    'public' => [
         'driver' => '<my-custom-driver>',
         'searchables' => 'collection:<my-collection-name>',
         'fields' => ['title', 'description'],
    ],
],

[jasonvarga]

I was hesitant to merge because it would make the order of arguments different from a similar situation in Laravel.

This is what it would look like now for us when registering a custom search index:

Search::extend('elasticsearch', function ($app, $config, $name) {

In Laravel:

But when keys aren't necessary, the $config comes first:

And sometimes it's completely different anyway:

So 🤷 we'll go with what you've done. Thanks!