chore(deps): update actions/download-artifact action to v5

Author: renovate[bot]

.github/workflows/ci.yml

@@ -212,7 +212,7 @@ jobs:
         run: pnpm --filter=livekit-server-sdk build
 
       - name: Download all artifacts
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v5
         with:
           path: packages/livekit-rtc/artifacts