Bump serde from 1.0.208 to 1.0.209 in /lang/rust (#3120)

Bumps [serde](https://github.com/serde-rs/serde) from 1.0.208 to 1.0.209.
- [Release notes](https://github.com/serde-rs/serde/releases)
- [Commits](serde-rs/serde@v1.0.208...v1.0.209)

---
updated-dependencies:
- dependency-name: serde
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

lang/rust/Cargo.toml

@@ -42,7 +42,7 @@ documentation = "https://docs.rs/apache-avro"
 # dependencies used by more than one members
 [workspace.dependencies]
 log = { default-features = false, version = "0.4.22" }
-serde = { default-features = false, version = "1.0.208", features = ["derive"] }
+serde = { default-features = false, version = "1.0.209", features = ["derive"] }
 serde_bytes = { default-features = false, version = "0.11.15", features = ["std"] }
 serde_json = { default-features = false, version = "1.0.125", features = ["std"] }