Update TOC.yml

Author: cherylmc

articles/virtual-wan/TOC.yml

@@ -130,6 +130,8 @@
     href: hub-settings.md
   - name: Gateway settings
     href: gateway-settings.md
+  - name: Apply Zero Trust principles
+    href: /security/zero-trust/azure-virtual-wan?toc=%2fazure%2fvirtual-wan%2ftoc.json&bc=/azure/virtual-wan/breadcrumb/toc.json
   - name: Secured virtual hubs
     href: ../firewall-manager/secured-virtual-hub.md?toc=%2fazure%2fvirtual-wan%2ftoc.json&bc=/azure/virtual-wan/breadcrumb/toc.json
   - name: Security baseline