Bump serde from 1.0.166 to 1.0.168 (solana-labs#32436)

Bumps [serde](https://github.com/serde-rs/serde) from 1.0.166 to 1.0.168.
- [Release notes](https://github.com/serde-rs/serde/releases)
- [Commits](serde-rs/serde@v1.0.166...v1.0.168)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: dependabot-buildkite <dependabot-buildkite@noreply.solana.com>
Signed-off-by: Illia Bobyr <illia.bobyr@solana.com>

Cargo.toml

@@ -279,7 +279,7 @@ rustls = { version = "0.20.8", default-features = false }
 rustversion = "1.0.13"
 scopeguard = "1.1.0"
 semver = "1.0.17"
-serde = "1.0.166"
+serde = "1.0.168"
 serde_bytes = "0.11.11"
 serde_derive = "1.0.103"
 serde_json = "1.0.100"