Update test matrix to use Carbon 3.8 for Laravel 12 compatibility

Author: rokde

.github/workflows/run-tests.yml

@@ -23,7 +23,7 @@ jobs:
         include:
           - laravel: 12.*
             testbench: 10.*
-            carbon: ^2.63
+            carbon: ^3.8
 
     name: P${{ matrix.php }} - L${{ matrix.laravel }} - ${{ matrix.stability }} - ${{ matrix.os }}