chore: checkpoint before Python removal

vendor/serde_urlencoded/README.md

@@ -0,0 +1,53 @@
+`x-www-form-urlencoded` meets Serde
+===================================
+
+This crate is a Rust library for serialising to and deserialising from
+the [`application/x-www-form-urlencoded`][urlencoded] format. It is built
+upon [Serde], a high performance generic serialization framework and [rust-url],
+a URL parser for Rust.
+
+[rust-url]: https://github.com/servo/rust-url
+[Serde]: https://github.com/serde-rs/serde
+[urlencoded]: https://url.spec.whatwg.org/#application/x-www-form-urlencoded
+
+Installation
+============
+
+This crate works with Cargo and can be found on
+[crates.io] with a `Cargo.toml` like:
+
+```toml
+[dependencies]
+serde_urlencoded = "0.7"
+```
+
+The documentation is available on [docs.rs].
+
+[crates.io]: https://crates.io/crates/serde_urlencoded
+[docs.rs]: https://docs.rs/serde_urlencoded/0.7.1/serde_urlencoded/
+
+## Getting help
+
+Serde developers live in the #serde channel on
+[`irc.mozilla.org`](https://wiki.mozilla.org/IRC) and most rust-url developers
+live in the #servo one. The #rust channel is also a good resource with generally
+faster response time but less specific knowledge about Serde, rust-url or this
+crate. If IRC is not your thing, we are happy to respond to [GitHub
+issues](https://github.com/nox/serde_urlencoded/issues/new) as well.
+
+## License
+
+serde_urlencoded 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 serde_urlencoded by you, as defined in the Apache-2.0 license,
+shall be dual licensed as above, without any additional terms or conditions.