Bump env_logger from 0.8.4 to 0.9.0 (#3608)

Bumps [env_logger](https://github.com/env-logger-rs/env_logger) from 0.8.4 to 0.9.0.
- [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/v0.8.4...v0.9.0)

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

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

polkadot/utils/staking-miner/Cargo.toml

@@ -8,7 +8,7 @@ edition = "2018"
 codec = { package = "parity-scale-codec", version = "2.0.0" }
 tokio = { version = "0.2", features = ["macros"] }
 log = "0.4.11"
-env_logger = "0.8.3"
+env_logger = "0.9.0"
 structopt = "0.3.0"
 jsonrpsee-ws-client = { version = "0.3.0", default-features = false, features = ["tokio02"] }
 serde_json = "1.0"