update readme for open source requirements (#1059)

Author: jennyf19

README.md

@@ -64,4 +64,8 @@ This library controls how users sign-in and access services. We recommend you al
 
 If you find a security issue with our libraries or services, please report it to [[email protected]](mailto:[email protected]) with as much detail as possible. Your submission may be eligible for a bounty through the [Microsoft Bounty](http://aka.ms/bugbounty) program. Please do not post security issues to GitHub Issues or any other public site. We will contact you shortly upon receiving the information. We encourage you to get notifications of when security incidents occur by visiting [this page](https://technet.microsoft.com/en-us/security/dd252948) and subscribing to Security Advisory Alerts.
 
+## Trademarks.
+
+This project may contain trademarks or logos for projects, products, or services. Authorized use of Microsoft trademarks or logos is subject to and must follow [Microsoft's Trademark & Brand Guidelines](https://www.microsoft.com/en-us/legal/intellectualproperty/trademarks/usage/general). Use of Microsoft trademarks or logos in modified versions of this project must not cause confusion or imply Microsoft sponsorship. Any use of third-party trademarks or logos are subject to those third-party's policies.
+
 Copyright (c) Microsoft Corporation.  All rights reserved. Licensed under the MIT License (the "License").