ci: Update to PHP 8.5

Author: linc

.github/workflows/php.yml

@@ -12,7 +12,9 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: shivammathur/setup-php@v2
+      with:
+        php-version: '8.5'
 
     - name: Validate composer.json and composer.lock
       run: composer validate --strict