docs: indicate the license options (MIT, Apache 2.0, or Unlicense) of the project

README.md

@@ -29,3 +29,12 @@ To be more specific about what a breaking change _could_ entail:
 - changing the expected result of an existing integration test (not sure if unit tests would count)
 
 All the crates in this project have a [minimum supported Rust version (MSRV)](https://rust-lang.github.io/rfcs/2495-min-rust-version.html) of 1.76, the release succeeding [the one that stabilized `async fn` in traits](https://blog.rust-lang.org/2023/12/28/Rust-1.75.0.html) (which the `core` crate of this project is expected to make use of). I [intend to test this in CI (GitHub Actions) in the future](https://github.com/babichjacob/ac-qu-ai-nt/issues/5) to identify if it ever gets raised by changes but I have not set this up yet. Raising the MSRV will be considered a breaking change --- my justification is that it [seems more appropriate for an application like this](https://github.com/matklad/once_cell/issues/201#issuecomment-1257213601). This may be reconsidered if [Cargo's MSRV-aware resolver](https://rust-lang.github.io/rfcs/3537-msrv-resolver.html) is stabilized.
+
+## License
+
+All contents of this repository are licensed under either the
+* [MIT license](LICENSE-MIT), or
+* [Apache 2.0 license](LICENSE-APACHE), or
+* [Unlicense](LICENSE-UNLICENSE)
+
+at your option.