LICENSE.txt does not include author or year

[ulfben]

Hi Melissa,

Thank you for your work on PCG - your random generators are a fantastic resource!

I noticed that LICENSE.txt in this repository doesn’t include an author or year, which is sometimes required for clarity in downstream projects.

Also, I saw that later PCG repositories are dual-licensed (MIT/Apache 2.0), which is very helpful for projects aiming to maintain a consistent licensing model. Would you consider updating this repo to the same dual-licensing approach?

Thanks so much for considering it, and for sharing such excellent work!

Best regards,
Ulf