gha: test with PHP 8.5

Author: mfn

.github/workflows/integration_tests.yml

@@ -25,7 +25,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: [8.2, 8.3, 8.4]
+        php: [8.2, 8.3, 8.4, 8.5]
         laravel: [^11.0, ^12.0]
     name: P=${{ matrix.php }} L=${{ matrix.laravel }}
     runs-on: ubuntu-latest