Update how-to-perform-major-version-upgrade-portal.md

Fix

Author: kabharati

articles/postgresql/flexible-server/how-to-perform-major-version-upgrade-portal.md

@@ -18,7 +18,7 @@ This article provides a step-by-step procedure to perform Major Version Upgrade
 > [!NOTE]  
 > Major Version Upgrade action is irreversible. Please perform a Point-In-Time Recovery (PITR) of your production server and test the upgrade in the non-production environment.
 
-Follow these steps to upgrade your flexible server to the major version of your choice:
+## Follow these steps to upgrade your flexible server to the major version of your choice: