Update upload artifacts

.github/workflows/ci.yml

@@ -43,7 +43,7 @@ jobs:
       # And lastly, we upload the generated build/ folder as artifact so we can
       # use it in later steps.
       - name: Upload build and .svelte-kit folder
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
           name: build
           if-no-files-found: error
@@ -61,7 +61,7 @@ jobs:
     steps:
       # No need to checkout the project, since all we need is to download the
       # build artifact from the build step.
-      - uses: actions/download-artifact@v2
+      - uses: actions/download-artifact@v4
         with:
           name: build
           path: build