Bump tokio from 1.19.2 to 1.20.0 in /src/proxy-manager (#2164)

Bumps [tokio](https://github.com/tokio-rs/tokio) from 1.19.2 to 1.20.0.
- [Release notes](https://github.com/tokio-rs/tokio/releases)
- [Commits](tokio-rs/tokio@tokio-1.19.2...tokio-1.20.0)

---
updated-dependencies:
- dependency-name: tokio
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

src/proxy-manager/Cargo.toml

@@ -16,7 +16,7 @@ serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 storage-queue = { path = "../agent/storage-queue" }
 thiserror = "1.0"
-tokio = { version = "1.19", features = ["macros", "rt-multi-thread", "fs", "process"] }
+tokio = { version = "1.20", features = ["macros", "rt-multi-thread", "fs", "process"] }
 url = { version = "2.2", features = ["serde"] }
 reqwest-retry = { path = "../agent/reqwest-retry"}
 onefuzz-telemetry = { path = "../agent/onefuzz-telemetry" }