Bump config from 0.14.0 to 0.15.6

Bumps [config](https://github.com/rust-cli/config-rs) from 0.14.0 to 0.15.6.
- [Changelog](https://github.com/rust-cli/config-rs/blob/main/CHANGELOG.md)
- [Commits](rust-cli/config-rs@0.14.0...v0.15.6)

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

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

Author: dependabot[bot]

Cargo.lock

@@ -14,7 +14,7 @@ clap = { version = "4", features = ["derive"] }
 tokio = { version = "1", features = ["full"] }
 tokio-util = { version = "0.7", features = ["codec", "net"] }
 futures = "0.3"
-config = "0.14"
+config = "0.15"
 serde = { version = "1", features = ["derive"] }
 whisper = { path = "../whisper" }