Bump dbus from 0.9.3 to 0.9.4

Bumps [dbus](https://github.com/diwic/dbus-rs) from 0.9.3 to 0.9.4.
- [Release notes](https://github.com/diwic/dbus-rs/releases)
- [Commits](https://github.com/diwic/dbus-rs/compare/dbus-v0.9.3...dbus-v0.9.4)

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

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

Cargo.toml

@@ -36,7 +36,7 @@ tokio = { version = "1", features = ["rt-multi-thread", "sync", "time"] }
 tokio-stream = "0.1.7"
 toml = "0.5"
 unicode-width = "0.1.9"
-dbus = { version = "0.9.3", optional = true }
+dbus = { version = "0.9.4", optional = true }
 dbus-tree = { version = "0.9.0", optional = true }
 rand = "0.8"
 webbrowser = "0.5"