chore: Add license and contribution in readme. (#80)

To be consistent with the other repos.

Author: rklaehn

README.md

@@ -20,4 +20,21 @@ See the [module docs](https://docs.rs/irpc/latest/irpc/).
 # Docs
 
 Properly building docs for this crate is quite complex. For all the gory details,
-see [DOCS.md].
+see [DOCS.md].
+
+## License
+
+Copyright 2025 N0, INC.
+
+This project is licensed under either of
+
+ * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
+   http://www.apache.org/licenses/LICENSE-2.0)
+ * MIT license ([LICENSE-MIT](LICENSE-MIT) or
+   http://opensource.org/licenses/MIT)
+
+at your option.
+
+## Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this project by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.