fix h1 into h2

Author: diberry

articles/cognitive-services/QnAMaker/How-To/collaborate-knowledge-base.md

@@ -9,7 +9,7 @@ ms.date: 03/17/2020
 
 Collaboration is provided at the QnA Maker resource level to allow you to restrict collaborator access based on the collaborator's role. Learn more about QnA Maker collaborator authentication [concepts](../Concepts/role-based-access-control.md).
 
-# Add role-based access (RBAC) to your QnA Maker resource
+## Add role-based access (RBAC) to your QnA Maker resource
 
 QnA Maker allows multiple people to collaborate on all knowledge bases in the same QnA Maker resource. This feature is provided with the Azure [Role-Based Access Control](../../../active-directory/role-based-access-control-configure.md).