Please add a LICENSE

[samtstern]

This repository does not have a LICENSE which means we can no longer list it on https://devlibrary.withgoogle.com/ and makes it harder for people to use with confidence.

If you add a license (Apache 2.0 or MIT) please file an issue on https://github.com/google/devlibrary so that we can add your project to the site.

[willi84]

⚠️note for myself: needs to be discussed with the original authors and the author of the stackblitz samples