Fix CI deprecation (#181)

Author: norkunas

.github/workflows/ci.yml

@@ -78,7 +78,7 @@ jobs:
                       symfony-version: 7.0.*
         steps:
             - name: "Checkout"
-              uses: actions/checkout@v2
+              uses: actions/checkout@v4
 
             - name: "Setup PHP"
               uses: shivammathur/setup-php@v2