Provide License Information

[JoHae]

First of all, thank you for providing this library extension.

Background - Use-Case:
I would like to add your library to a (until now private) application that I am building, which basically adds a Web-Application to configure Network-Settings and lets you control (play) Web-Radios from your smartphone. It already works very fine. In using your lib extension it would reach a new degree of awesomeness :).

However, I would also like to make the application publicly available, so I am kindly asking you to provide license information in order to be on the safe side.

Recommendation:
Since the original code uses GNU Public license (https://github.com/Edzelf/ESP32-Radio/blob/master/LICENSE) you can just add a GNU license and state your changes (see conditions of license). That should be enough I guess.

Merry Christmas and Happy Holidays