fix: Use Carbon ^3.8.4 constraint in workflow

- Carbon 3.0 has security advisory and conflicts with Laravel 11/12
- Both Laravel 11 and 12 require nesbot/carbon ^3.8.4

Author: HPWebdeveloper

.github/workflows/run-tests.yml

@@ -19,10 +19,10 @@ jobs:
         include:
           - laravel: 11.*
             testbench: 9.*
-            carbon: ^3.0
+            carbon: ^3.8.4
           - laravel: 12.*
             testbench: 10.*
-            carbon: ^3.0
+            carbon: ^3.8.4
 
     name: P${{ matrix.php }} - L${{ matrix.laravel }} - ${{ matrix.stability }} - ${{ matrix.os }}