Update dirs requirement from ~3.0 to ~4.0

Updates the requirements on [dirs](https://github.com/soc/dirs-rs) to permit the latest version.
- [Release notes](https://github.com/soc/dirs-rs/releases)
- [Commits](https://github.com/soc/dirs-rs/commits)

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

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

tools/cli/Cargo.toml

@@ -20,7 +20,7 @@ test = false
 
 [dependencies]
 combine = "~4.6"
-dirs = "~3.0"
+dirs = "~4.0"
 env_logger = "~0.9"
 failure = "~0.1"
 failure_derive = "~0.1"