Update CI workflow to use artifacts v4

Author: object-Object

.github/workflows/ci.yml

@@ -48,7 +48,7 @@ jobs:
         run: xvfb-run --auto-servernum hexdoc ci build
 
       - name: Upload package artifact
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: python-build
           path: dist
@@ -120,7 +120,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Download package artifact
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
           name: python-build
           path: dist