build(deps): update toml requirement from 0.7 to 0.8

Updates the requirements on [toml](https://github.com/toml-rs/toml) to permit the latest version.
- [Commits](toml-rs/toml@toml-v0.7.0...toml-v0.8.2)

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

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

quic/s2n-quic-sim/Cargo.toml

@@ -24,5 +24,5 @@ s2n-quic-core = { path = "../s2n-quic-core", features = ["testing"] }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 structopt = "0.3"
-toml = "0.7"
+toml = "0.8"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }