update Illuminate\Support\ServiceProvider::mergeConfigFrom() to merge/replace recursively

[pintend]

current method mergeConfigFrom() overwrites any duplicate keys between vendor and published config with the published config (which is what you want) the problem is when values are arrays, vendor cant (afaik) cleanly add values in the subarrays, this can be useful if any future package update has config keys that are in a subarray but not in the published config file (yes I know about default values if config key is missing) and if you want to update values in any other config file, e.g. add a database connection or auth provider/guard

Say I have a vendor/.../apple.php

return [
    'key1' => 'someValue',
    'key2' => [
        'subKey1' => 'default',
        'subKey2' => 'someOtherValue',
    ],
];

in published config/apple.php

return [
    'key2' => [
        'subKey1' => 'updatedValue',
    ],
];

With array_merge() the expected result is missing "subKey2" as "key2" is overwritten

[
     "key1" => "someValue",
     "key2" => [
       "subKey1" => "updatedValue",
     ],
]

I think it makes sense to have "subKey2" unless it is explicitly removed 'subKey2' => NULL

with array_replace_recursive() the expected result is

[
    'key1' => 'someValue',
    'key2' => [
        'subKey1' => 'updatedValue',
        'subKey2' => 'someOtherValue',
    ],
]

current method: in Illuminate\Support\ServiceProvider::mergeConfigFrom()

    /**
     * Merge the given configuration with the existing configuration.
     *
     * @param  string  $path
     * @param  string  $key
     * @return void
     */
    protected function mergeConfigFrom($path, $key)
    {
        if (! ($this->app instanceof CachesConfiguration && $this->app->configurationIsCached())) {
            $config = $this->app->make('config');

            $config->set($key, array_merge(
                require $path, $config->get($key, [])
            ));
        }
    }

updated:

            $config->set($key, array_replace_recursive(
                require $path, $config->get($key, [])
            ));

Maybe this shouldn't be the default case, if so then maybe add another method recursiveMergeConfigFrom()