Bump syn from 2.0.28 to 2.0.29 in /lang/rust (#2453)

Bumps [syn](https://github.com/dtolnay/syn) from 2.0.28 to 2.0.29.
- [Release notes](https://github.com/dtolnay/syn/releases)
- [Commits](dtolnay/syn@2.0.28...2.0.29)

---
updated-dependencies:
- dependency-name: syn
  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>
(cherry picked from commit dccead7)

lang/rust/avro_derive/Cargo.toml

@@ -37,7 +37,7 @@ darling = { default-features = false, version = "0.20.3" }
 proc-macro2 = { default-features = false, version = "1.0.66" }
 quote = { default-features = false, version = "1.0.32" }
 serde_json = { default-features = false, version = "1.0.105", features = ["std"] }
-syn = { default-features = false, version = "2.0.28", features = ["full", "fold"] }
+syn = { default-features = false, version = "2.0.29", features = ["full", "fold"] }
 
 [dev-dependencies]
 apache-avro = { default-features = false, path = "../avro", features = ["derive"] }