chore(deps): bump hex-literal from 0.3.1 to 0.3.4

Bumps [hex-literal](https://github.com/RustCrypto/utils) from 0.3.1 to 0.3.4.
- [Release notes](https://github.com/RustCrypto/utils/releases)
- [Commits](RustCrypto/utils@hex-literal-v0.3.1...hex-literal-v0.3.4)

---
updated-dependencies:
- dependency-name: hex-literal
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

Cargo.lock

@@ -46,7 +46,7 @@ once_cell = "1.5.2"
 codec = { package = "parity-scale-codec", version = "2.0.0" }
 serde = { version = "1.0.102", features = ["derive"] }
 futures = { version = "0.3.9", features = ["compat"] }
-hex-literal = "0.3.1"
+hex-literal = "0.3.4"
 log = "0.4.8"
 rand = "0.7.2"
 structopt = { version = "0.3.8", optional = true }