add akamai retirement faq entry

Author: duongau

articles/frontdoor/TOC.yml

@@ -232,6 +232,8 @@
     items:
     - name: Migrate CDN provider
       href: ../cdn/cdn-change-provider.md?toc=/azure/frontdoor/TOC.json
+    - name: Akamai retirement FAQ
+      href: ../cdn/akamai-retirement-faq.md?toc=/azure/frontdoor/TOC.json
     - name: Security baseline
       href: /security/benchmark/azure/baselines/content-delivery-network-security-baseline?toc=/azure/frontdoor/TOC.json
     - name: DDoS protection