Update async-channel requirement from 1.6 to 2.3

Updates the requirements on [async-channel](https://github.com/smol-rs/async-channel) to permit the latest version.
- [Release notes](https://github.com/smol-rs/async-channel/releases)
- [Changelog](https://github.com/smol-rs/async-channel/blob/master/CHANGELOG.md)
- [Commits](smol-rs/async-channel@v1.6.0...v2.3.1)

---
updated-dependencies:
- dependency-name: async-channel
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Cargo.toml

@@ -114,7 +114,7 @@ harness = false
 required-features = ["async-std-runtime", "testing"]
 
 [dependencies]
-async-channel = { version = "1.6", optional = true }
+async-channel = { version = "2.3", optional = true }
 clap = { version = "3.2", optional = true }
 futures = "0.3"
 inventory = { version = "0.3", optional = true }