Update self_update requirement from 0.37.0 to 0.39.0

Updates the requirements on [self_update](https://github.com/jaemk/self_update) to permit the latest version.
- [Release notes](https://github.com/jaemk/self_update/releases)
- [Changelog](https://github.com/jaemk/self_update/blob/master/CHANGELOG.md)
- [Commits](https://github.com/jaemk/self_update/commits)

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

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

jig-cli/Cargo.toml

@@ -13,7 +13,7 @@ gix = { version = "0.48.0", default-features = false }
 inquire = { git = "https://github.com/mikaelmello/inquire.git", features = ["date"] }
 jira = { path = "../jira", default-features = false }
 regex = { workspace = true }
-self_update = { version = "0.37.0", default-features = false, features = ["rustls"] }
+self_update = { version = "0.39.0", default-features = false, features = ["rustls"] }
 serde = { workspace = true }
 serde_json = { workspace = true }
 toml = "0.8.6"