Bump crossbeam-channel from 0.3.9 to 0.4.2 (#8930)

Bumps [crossbeam-channel](https://github.com/crossbeam-rs/crossbeam) from 0.3.9 to 0.4.2.
- [Release notes](https://github.com/crossbeam-rs/crossbeam/releases)
- [Changelog](https://github.com/crossbeam-rs/crossbeam/blob/v0.4.2/CHANGELOG.md)
- [Commits](https://github.com/crossbeam-rs/crossbeam/compare/crossbeam-channel-0.3.9...v0.4.2)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Cargo.lock

@@ -3574,7 +3574,7 @@ name = "solana-accounts-bench"
 version = "1.1.0"
 dependencies = [
  "clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "crossbeam-channel 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-channel 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",

accounts-bench/Cargo.toml

@@ -16,4 +16,4 @@ solana-measure = { path = "../measure", version = "1.1.0" }
 solana-sdk = { path = "../sdk", version = "1.1.0" }
 rand = "0.6.5"
 clap = "2.33.0"
-crossbeam-channel = "0.3"
+crossbeam-channel = "0.4"