Bump async-trait from 0.1.50 to 0.1.51 (#3721)

Bumps [async-trait](https://github.com/dtolnay/async-trait) from 0.1.50 to 0.1.51.
- [Release notes](https://github.com/dtolnay/async-trait/releases)
- [Commits](https://github.com/dtolnay/async-trait/compare/0.1.50...0.1.51)

---
updated-dependencies:
- dependency-name: async-trait
  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>

polkadot/node/network/bridge/Cargo.toml

@@ -5,7 +5,7 @@ authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
 [dependencies]
-async-trait = "0.1.42"
+async-trait = "0.1.51"
 futures = "0.3.15"
 tracing = "0.1.26"
 polkadot-primitives = { path = "../../../primitives" }

polkadot/node/network/dispute-distribution/Cargo.toml

@@ -25,7 +25,7 @@ rand = "0.8.3"
 lru = "0.6.6"
 
 [dev-dependencies]
-async-trait = "0.1.42"
+async-trait = "0.1.51"
 polkadot-subsystem-testhelpers = { package = "polkadot-node-subsystem-test-helpers", path = "../../subsystem-test-helpers" }
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master", features = ["std"] }
 sp-keyring = { git = "https://github.com/paritytech/substrate", branch = "master" }

polkadot/node/network/protocol/Cargo.toml

@@ -6,7 +6,7 @@ edition = "2018"
 description = "Primitives types for the Node-side"
 
 [dependencies]
-async-trait = "0.1.42"
+async-trait = "0.1.51"
 polkadot-primitives = { path = "../../../primitives" }
 polkadot-node-primitives = { path = "../../primitives" }
 polkadot-node-jaeger = { path = "../../jaeger" }