Please include a LICENSE

[penyuan]

Thank you @rixx for creating such a useful tool!

Can an open source LICENSE be added to the code, whether as a LICENSE file in this repository (super easy) or at least as a SPDX-formatted comment at the beginning of the script? For example:

# SPDX-License-Identifier: GPL-3.0-or-later

...or another license of the author's choosing from this list. Thanks!

I'm also happy to submit a pull request for this if the author can specify the license they prefer.