Added badge for license.

Author: garethj-msft

README.md

@@ -6,6 +6,8 @@ They may additionally create documents specific to their team, adding further gu
 We publish these guidelines here with the aim of fostering dialogue and learning in the API community at large.
 We further hope that these guidelines may encourage other organizations to create guidelines that are appropriate for them and in turn, if they are able, to publish theirs.
 
+[![License: CC BY 4.0](https://img.shields.io/badge/License-CC%20BY%204.0-lightgrey.svg)](https://creativecommons.org/licenses/by/4.0/)
+
 ## Code of Conduct
 This project has adopted the [Microsoft Open Source Code of Conduct](https://opensource.microsoft.com/codeofconduct/). For more information see the [Code of Conduct FAQ](https://opensource.microsoft.com/codeofconduct/faq/) or contact [[email protected]](mailto:[email protected]) with any additional questions or comments.