Update env_logger requirement from 0.8 to 0.9

Updates the requirements on [env_logger](https://github.com/env-logger-rs/env_logger) to permit the latest version.
- [Release notes](https://github.com/env-logger-rs/env_logger/releases)
- [Changelog](https://github.com/env-logger-rs/env_logger/blob/main/CHANGELOG.md)
- [Commits](rust-cli/env_logger@v0.8.0...v0.9.0)

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

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

Cargo.toml

@@ -51,7 +51,7 @@ parity-wasm = { version = "0.42", default-features = false }
 
 # Dependencies only used by the binaries
 clap = { version = "2", optional = true }
-env_logger = { version = "0.8", optional = true }
+env_logger = { version = "0.9", optional = true }
 glob = { version = "0.3", optional = true }
 lazy_static = { version = "1", optional = true }