chore: bump checkout and configure-pages to node 24 versions

The checkout action was bumped from v4 to v6 and configure-pages from v5 to v6
in the deployment workflow. Both v6 releases ship with Node.js 24 support.

GitHub will force all actions to run on Node.js 24 starting June 2026 and remove
Node.js 20 from runners in September 2026. Upgrading now avoids the deprecation
warnings and ensures the workflow keeps working after the cutoff dates.

Author: vidalvasconcelos

.github/workflows/deployment.yaml

@@ -20,10 +20,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: "Setup Pages"
-        uses: actions/configure-pages@v5
+        uses: actions/configure-pages@v6
 
       - name: "Upload artifact"
         uses: actions/upload-pages-artifact@v4