License this under something

[est31]

Similar to the Rust RFCs repo, this repo should get a proper license. This point is better settled now than later if it has tens, maybe hundreds of contributors :).

I suggest going with Apache2.0/MIT just like for the Rust RFC's repo. Does that sound okay?

[carllerche]

The repo is licensed under MIT / Apache 2.0. The readme now reflects this. Thanks.

[est31]

Thank you!