add ps migration article to the toc

Author: halkazwini

articles/frontdoor/TOC.yml

@@ -161,8 +161,10 @@
       href: tier-migration.md
     - name: Classic to Standard/Premium mapping
       href: tier-mapping.md
-    - name: Migrate from Front Door (classic)
+    - name: Migrate from Front Door (classic) - Portal
       href: migrate-tier.md
+    - name: Migrate from Front Door (classic) - PowerShell
+      href: migrate-tier-powershell.md
   - name: Microsoft CDN (classic) retirement FAQ
     href: ../cdn/classic-cdn-retirement-faq.md
   - name: Edgio retirement FAQ