Include LICENSE

[lacabra]

Dear project maintainers,

First and foremost, thank you 🙏 for the amazing work that your team has made making carbon dioxide data more easily available to the general public, and open sourcing it! Kudos to you 🙌

In order for many others to build on your work, they need to know under which terms they can do so, and that's where including a LICENSE in your repo is immensely helpful, as it can actually make all the difference in whether they can use or not depending on what license do you release this project under.

Should you need any guidance in choosing a license, refer to https://choosealicense.com/

As additional context, I am the technical lead for @unicef's Digital Public Goods Alliance with the mission to facilitate the discovery, development, use of, and investment in, openly licensed technologies, data models, and content of high relevance for attainment of the Sustainable Development Goals (SDGs). We have been compiling nominations for Digital Public Goods, and I would very much like to include the State of Carbon, but we need you to explicit a license to do so.

Thanks again 🙏
Victor