Add license badge

Author: orltom

README.md

@@ -1,5 +1,6 @@
 # airlock-gateway-client-python
 ![](https://github.com/orltom/airlock-gateway-client-python/workflows/CI/badge.svg)
+[![License](https://img.shields.io/github/license/orltom/airlock-gateway-client-python)](/LICENSE)
 
 ## Module client
 Provide for each resource endpoint an rest api client.
@@ -43,4 +44,4 @@ Please use the [GitHub issue tracker](https://github.com/orltom/airlock-gateway-
 ## Disclaimer
 Copyright Orlando Tomás.
 
-Distributed under the terms of the MIT license, airlock-gateway-client is free and open source software.
+Distributed under the terms of the MIT license, airlock-gateway-client is free and open source software.