Update tower-http requirement from 0.3.2 to 0.4.0 (#315)

Updates the requirements on [tower-http](https://github.com/tower-rs/tower-http) to permit the latest version.
- [Release notes](https://github.com/tower-rs/tower-http/releases)
- [Commits](tower-rs/tower-http@tower-http-0.3.2...tower-http-0.4.0)

---
updated-dependencies:
- dependency-name: tower-http
  dependency-type: direct:production
...

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

Cargo.toml

@@ -38,7 +38,7 @@ cfg-if = "1.0.0"
 either = "1.8.0"
 hyper = { version = "0.14.13", features = ["client", "http1", "stream", "tcp"] }
 http = "0.2.5"
-tower-http = { version = "0.3.2", features = ["map-response-body", "trace"] }
+tower-http = { version = "0.4.0", features = ["map-response-body", "trace"] }
 hyper-timeout = {version = "0.4.1", optional = true }
 http-body = "0.4.5"
 tower = { version = "0.4.13", default-features = false, features = ["util", "buffer"] }