Don't test with 8.1 for Laravel 11

Author: inxilpro

.github/workflows/phpunit.yml

@@ -20,6 +20,9 @@ jobs:
             testbench: 8.*
           - laravel: 11.*
             testbench: 9.x-dev
+        exclude:
+          - laravel: 11.*
+            php: 8.1
 
     timeout-minutes: 10