Merge pull request #114 from BenjaminHoegh/copilot/update-github-actions-workflow

chore: update actions/checkout v4 → v6 to fix deprecated Node.js 20 runtime

Author: BenjaminHoegh

.github/workflows/ci.yaml

@@ -17,7 +17,7 @@ jobs:
 
     steps:
       - name: Checkout the source code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Set up PHP
         uses: shivammathur/setup-php@v2