:wrench: Slugify new session.cookie to comply with RFC 6265.

config/session.php

@@ -122,7 +122,7 @@ return [
     |
     */
 
-    'cookie' => env('SESSION_COOKIE', snake_case(env('APP_NAME', 'laravel')).'_session'),
+    'cookie' => env('SESSION_COOKIE', str_slug(env('APP_NAME', 'laravel'), '_').'_session'),
 
     /*
     |--------------------------------------------------------------------------