chore: bump futures-util from 0.3.19 to 0.3.21 (#23418)

* chore: bump futures-util from 0.3.19 to 0.3.21

Bumps [futures-util](https://github.com/rust-lang/futures-rs) from 0.3.19 to 0.3.21.
- [Release notes](https://github.com/rust-lang/futures-rs/releases)
- [Changelog](https://github.com/rust-lang/futures-rs/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rust-lang/futures-rs/compare/0.3.19...0.3.21)

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

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

* [auto-commit] Update all Cargo lock files

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: dependabot-buildkite <dependabot-buildkite@noreply.solana.com>

client-test/Cargo.toml

@@ -10,7 +10,7 @@ documentation = "https://docs.rs/solana-client-test"
 edition = "2021"
 
 [dependencies]
-futures-util = "0.3.19"
+futures-util = "0.3.21"
 serde_json = "1.0.78"
 serial_test = "0.6.0"
 solana-client = { path = "../client", version = "=1.10.0" }