exclude testbench 6.* from laravel 11.*

Author: johguentner

.github/workflows/main.yml

@@ -27,6 +27,8 @@ jobs:
             php: "8.1"
           - laravel: "8.*"
             testbench: "9.*"
+          - laravel: "11.*"
+            testbench: "6.*"
 
     name: P${{ matrix.php }} - L${{ matrix.laravel }} - ${{ matrix.dependency-version }} - ubuntu-latest