Bump actions/checkout dependency

Author: W0rma

.github/workflows/main.yml

@@ -15,7 +15,7 @@ jobs:
 
     steps:
     - name: Checkout code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Setup PHP
       uses: shivammathur/setup-php@v2