Bump dbus from 0.9.0 to 0.9.1

Bumps [dbus](https://github.com/diwic/dbus-rs) from 0.9.0 to 0.9.1.
- [Release notes](https://github.com/diwic/dbus-rs/releases)
- [Commits](https://github.com/diwic/dbus-rs/compare/dbus-v0.9.0...dbus-v0.9.1)

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

Cargo.toml

@@ -36,7 +36,7 @@ toml = "0.5"
 tokio-core = "0.1"
 tokio-timer = "0.2"
 unicode-width = "0.1.8"
-dbus = { version = "0.9.0", optional = true }
+dbus = { version = "0.9.1", optional = true }
 dbus-tree = { version = "0.9.0", optional = true }
 rand = "0.8"
 webbrowser = "0.5"