Upgrade framework to laravel 9

app/Http/Kernel.php

@@ -58,7 +58,6 @@ class Kernel extends HttpKernel
         'bindings' => \Illuminate\Routing\Middleware\SubstituteBindings::class,
         'cache.headers' => \Illuminate\Http\Middleware\SetCacheHeaders::class,
         'can' => \Illuminate\Auth\Middleware\Authorize::class,
-        'demoMode' => \Spatie\DemoMode\DemoMode::class,
         'guest' => \App\Http\Middleware\RedirectIfAuthenticated::class,
         'role' => \App\Http\Middleware\Role::class,
         'signed' => \Illuminate\Routing\Middleware\ValidateSignature::class,