Update async-channel requirement from 1.7.0 to 2.1.0

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@v1.7.0...v2.1.0)

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

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

cameleon/Cargo.toml

@@ -20,7 +20,7 @@ thiserror = "1.0.24"
 semver = "1.0.0"
 zip = "0.6.0"
 sha-1 = "0.10.0"
-async-channel = "1.7.0" # 1.7.0 has added recv_blocking()
+async-channel = "1.7.0" # 2.1.0 has added recv_blocking()
 tracing = "0.1.26"
 auto_impl = "1.0.1"
 cameleon-device = { path = "../device", version = "0.1.12" }