Update TOC.yml

Author: irenehua

articles/load-balancer/TOC.yml

@@ -144,6 +144,8 @@
       href: move-across-regions-internal-load-balancer-portal.md
     - name: Internal load balancer - PowerShell
       href: move-across-regions-internal-load-balancer-powershell.md
+    - name: Upgrade a Basic Public Load Balancer to Standard Public Load Balancer
+      href: upgrade-basic-standard.md     
   - name: Troubleshoot
     items:
     - name: Troubleshoot Azure Load Balancer