Bump tokio from 1.20.3 to 1.20.4 in /rust

Bumps [tokio](https://github.com/tokio-rs/tokio) from 1.20.3 to 1.20.4.
- [Release notes](https://github.com/tokio-rs/tokio/releases)
- [Commits](tokio-rs/tokio@tokio-1.20.3...tokio-1.20.4)

---
updated-dependencies:
- dependency-name: tokio
  dependency-type: direct:production
...

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

Author: dependabot[bot]

rust/Cargo.lock

@@ -7,6 +7,6 @@ edition = "2018"
 [dependencies]
 futures = "0.3.21"
 lapin = "2.1.1"
-tokio = { version = "1.20.3", features = ["full"] }
+tokio = { version = "1.20.4", features = ["full"] }
 uuid = { version = "1.1.1", features = ["v4"] }
 tokio-stream = "0.1"