Parameterize PHP version in linting workflow

Author: simonhamp

.github/workflows/linting.yaml

@@ -20,7 +20,7 @@ jobs:
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: '8.3'
+          php-version: ${{ matrix.php }}
           tools: composer:v2
 
       - name: Copy .env