Bump env_logger from 0.8.2 to 0.8.4 (#3298)

Bumps [env_logger](https://github.com/env-logger-rs/env_logger) from 0.8.2 to 0.8.4.
- [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](https://github.com/env-logger-rs/env_logger/compare/v0.8.2...v0.8.4)

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

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

polkadot/node/subsystem-util/Cargo.toml

@@ -35,7 +35,7 @@ substrate-prometheus-endpoint = { git = "https://github.com/paritytech/substrate
 [dev-dependencies]
 assert_matches = "1.4.0"
 async-trait = "0.1.42"
-env_logger = "0.8.2"
+env_logger = "0.8.4"
 futures = { version = "0.3.15", features = ["thread-pool"] }
 log = "0.4.13"
 parking_lot = "0.11.1"