LaravelFCM\FCMServiceProvider::boot PHP Method

    public function boot()
    {
        if (str_contains($this->app->version(), 'Lumen')) {
            $this->app->configure('fcm');
        } else {
            $this->publishes([__DIR__ . "/../config/fcm.php" => config_path('fcm.php')]);
        }
    }