Update run-integration-tests.yml to include Laravel 12

Author: jonnott

.github/workflows/run-integration-tests.yml

@@ -20,7 +20,7 @@ jobs:
             fail-fast: false
             matrix:
                 php: [8.4, 8.3, 8.2]
-                laravel: [^11.15]
+                laravel: [^11.15, ^12.0]
 
         name: P${{ matrix.php }} - Laravel${{ matrix.laravel }}
         steps: