Bump serde_json from 1.0.49 to 1.0.51

Bumps [serde_json](https://github.com/serde-rs/json) from 1.0.49 to 1.0.51.
- [Release notes](https://github.com/serde-rs/json/releases)
- [Commits](https://github.com/serde-rs/json/compare/v1.0.49...v1.0.51)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

validator/Cargo.toml

@@ -14,7 +14,7 @@ chrono = { version = "0.4.11", features = ["serde"] }
 console = "0.10.0"
 log = "0.4.8"
 rand = "0.6.5"
-serde_json = "1.0.49"
+serde_json = "1.0.51"
 solana-clap-utils = { path = "../clap-utils", version = "1.2.0" }
 solana-client = { path = "../client", version = "1.2.0" }
 solana-core = { path = "../core", version = "1.2.0" }