Update web-app.yml (#1022)

Author: gvreddy04

.github/workflows/web-app.yml

@@ -47,7 +47,7 @@ jobs:
 
     steps:
       - name: Download artifact from build job
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
           name: .net-app