bump deploy-pages GitHub actions to v4

  Required now that we bumped the upload-pages-artifacts.

Author: KtorZ

.github/workflows/continuous-integration.yml

@@ -55,4 +55,4 @@ jobs:
     steps:
       - name: 🚀 Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v1
+        uses: actions/deploy-pages@v4