Adding a license?

[davidjb]

Thanks for publishing this Go module - it's been extremely helpful. Would it be possible for you to please add a license to the repository?

https://choosealicense.com/ is an outline made by GitHub that explains specifics, and Go projects typically use the 3-Clause BSD License, such as https://github.com/golang/go/blob/master/LICENSE in the official Go language.

Thanks very much!