Update LICENSE.md

Co-Authored-By: fkjagodzinski <fkjagodzinski@gmail.com>

LICENSE.md

@@ -36,7 +36,7 @@ The Python modules used by Mbed tools are used under the following licenses:
 - [six](https://pypi.org/project/six) - MIT
 - [mbed-cloud-sdk](https://pypi.org/project/mbed-cloud-sdk) - Apache 2.0
 - [requests](https://pypi.org/project/requests) - Apache-2.0
-- [idna](https://pypi.org/project/idna) - **TODO**, *BSD-like / BSD-style ?*
+- [idna](https://pypi.org/project/idna) - BSD-3-Clause
 - [pyserial](https://pypi.org/project/pyserial) - BSD-3-Clause
 - [Jinja2](https://pypi.org/project/Jinja2) - BSD-3-Clause
 - [intelhex](https://pypi.org/project/intelhex) - BSD