Update TOC.yml

Author: AlicjaKucharczyk

articles/postgresql/TOC.yml

@@ -659,7 +659,7 @@
         href: flexible-server/how-to-manage-high-availability-portal.md
       - name: Azure CLI
         href: flexible-server/how-to-configure-high-availability-cli.md
-    - name: major version upgrade
+    - name: Major version upgrade
       items:
       - name: Azure portal
         href: flexible-server/how-to-perform-major-version-upgrade-portal.md