Update tokio-test requirement from 0.2 to 0.3 (#12)

Updates the requirements on [tokio-test](https://github.com/tokio-rs/tokio) to permit the latest version.
- [Release notes](https://github.com/tokio-rs/tokio/releases)
- [Commits](tokio-rs/tokio@tokio-0.2.0...tokio-0.3.0)

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

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

Cargo.toml

@@ -23,7 +23,7 @@ uuid = { version = "^0.7", features = ["serde", "v4"] }
 futures = { version = "0.3.5", optional = true }
 futures-util = { version = "0.3.5", optional = true }
 tokio = { version = "0.2", features = ["macros"], optional = true }
-tokio-test = { version = "0.2", optional = true }
+tokio-test = { version = "0.3", optional = true }
 opentelemetry = { version = "0.8.0", optional = true }
 tracing = { version = "0.1.19", optional = true }
 tracing-opentelemetry = { version = "0.8.0", optional = true }