Update build.yml

Author: mythz

Diff for: .github/workflows/build.yml

@@ -35,7 +35,7 @@ jobs:
       - run: npm run build
 
       - name: Upload build artifact
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: servicestack-client
           path: |