🍏🚑 Fix composer failing on older PHP versions

Author: bramus

.github/workflows/CI.yml

@@ -17,9 +17,10 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v2
-      - uses: shivammathur/setup-php@2.9.0
+      - uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ matrix.php }}
+          tools: composer:2.2
       - name: Install dependencies
         run: composer update --no-interaction --prefer-dist ${{ matrix.dependencies }}
       - name: Configure PHPUnit problem matchers