Upgrade GitHub workflow actions

Author: ad-si

.github/workflows/pages.yml

@@ -26,7 +26,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Setup Pages
         uses: actions/configure-pages@v2
@@ -50,7 +50,7 @@ jobs:
         run: make docs
 
       - name: Upload artifact
-        uses: actions/upload-pages-artifact@v1
+        uses: actions/upload-artifact@v4
         with:
           path: docs