Use PHP 8.4 for CS checks

Author: aristath

.github/workflows/cs.yml

@@ -39,7 +39,7 @@ jobs:
       - name: Install PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: '7.4'
+          php-version: '8.4'
           coverage: none
           tools: cs2pr