fix: set minimum testbench for laravel 9.x

Author: joostdebruijn

.github/workflows/tests.yml

@@ -18,17 +18,13 @@ jobs:
           - laravel: 10.*
             testbench: 8.*
           - laravel: 9.*
-            testbench: 7.*
+            testbench: ^7.19
           - laravel: 8.*
             testbench: ^6.23
         exclude:
           # Laravel 10 doesn't support PHP 8.0
           - laravel: 10.*
             php: 8.0
-          # Laravel 9 on PHP 8.2 has problems with mistagged dependencies on prefer-lowest
-          - laravel: 9.*
-            php: 8.2
-            stability: prefer-lowest
           # Laravel 8 doesn't support PHP 8.2
           - laravel: 8.*
             php: 8.2