Update Rust crate serde to v1.0.204

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
serde (source)	dependencies	patch	1.0.203 -> 1.0.204

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Release Notes

serde-rs/serde (serde)

### [`v1.0.204`](https://togithub.com/serde-rs/serde/releases/tag/v1.0.204) [Compare Source](https://togithub.com/serde-rs/serde/compare/v1.0.203...v1.0.204) - Apply #\[diagnostic::on_unimplemented] attribute on Rust 1.78+ to suggest adding serde derive or enabling a "serde" feature flag in dependencies ([#​2767](https://togithub.com/serde-rs/serde/issues/2767), thanks [@​weiznich](https://togithub.com/weiznich))

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