Update livewire.blade.md (#259)

* Update livewire.blade.md

Update livewire integration instructions to refelect ivewire 3 changes.

* Update livewire.blade.md

* remove unnecessary indentation

---------

Co-authored-by: Samuel Štancl <samuel@archte.ch>

source/docs/v3/integrations/livewire.blade.md

@@ -22,6 +22,24 @@ to this:
 ],
 ```
 
+In Livewire 3, the configuration key `middleware_group` has been removed, so instead add the following in `TenancyServiceProvider` (or any other provider):
+
+```php
+public function boot(): void
+{
+    // ...
+
+    Livewire::setUpdateRoute(function ($handle) {
+        return Route::post('/livewire/update', $handle)
+            ->middleware(
+                'web',
+                'universal',
+                InitializeTenancyByDomain::class, // or whatever tenancy middleware you use
+            );
+    });
+}
+```
+
 (Don't forget to import the middleware class.)
 
 Now you can use Livewire both in the central app and the tenant app.