Tests: USBHID: Specify hidapi & pyusb licenses

Author: Filip Jagodzinski

LICENSE.md

@@ -22,3 +22,8 @@ Folders containing files under different permissive license than Apache 2.0 are
 - [TESTS/mbed_hal/trng/pithy](./TESTS/mbed_hal/trng/pithy) - BSD-3-Clause
 - [tools/data/rpc](./tools/data/rpc) - MIT
 - [targets](./targets) - PBL, BSD-style, MIT-style, Zlib-style, Public-domain
+
+The Python modules used by Mbed tools are used under the following licenses:
+
+- [pyusb](https://pypi.org/project/pyusb/) - Apache License 2.0
+- [hidapi](https://pypi.org/project/hidapi/) - BSD-style