Update GitHub checkout action to v4

Author: jnoordsij

.github/workflows/fix-cs.yml

@@ -18,7 +18,7 @@ jobs:
 
     steps:
     - name: Checkout code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Setup PHP
       uses: shivammathur/setup-php@v2

.github/workflows/run-integration-tests.yml

@@ -26,7 +26,7 @@ jobs:
         name: P${{ matrix.php }} - Lumen${{ matrix.lumen }}
         steps:
             - name: Checkout code
-              uses: actions/checkout@v3
+              uses: actions/checkout@v4
               with:
                   path: src
 
@@ -78,7 +78,7 @@ jobs:
         name: P${{ matrix.php }} - Laravel${{ matrix.laravel }}
         steps:
             - name: Checkout code
-              uses: actions/checkout@v3
+              uses: actions/checkout@v4
               with:
                   path: src
 

.github/workflows/run-tests.yml

@@ -35,7 +35,7 @@ jobs:
 
     steps:
     - name: Checkout code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Setup PHP
       uses: shivammathur/setup-php@v2