added redirection for renamed article

Author: anraghun

.openpublishing.redirection.json

@@ -21000,6 +21000,11 @@
             "redirect_url": "tutorial-prepare-vmware",
             "redirect_document_id": false
         },
+        {
+            "source_path_from_root": "/articles/migrate/tutorial-migrate-webapps.md",
+            "redirect_url": "/azure/migrate/tutorial-modernize-asp-net-appservice-code",
+            "redirect_document_id": false
+        },
         {
             "source_path_from_root": "/articles/site-recovery/concepts-vmware-to-azure-architecture.md",
             "redirect_url": "vmware-azure-architecture",