add setup-php to phpstan job

.github/workflows/ci.yml

@@ -107,6 +107,11 @@ jobs:
     name: Static analysis (PHPStan)
     runs-on: ubuntu-latest
     steps:
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.2'
+          extensions: imagick, swoole
       - uses: actions/checkout@v2
       - name: Install composer dependencies
         run: composer install