zbus: stick to 3.3, until !596 is fixed

qemu-rdw/Cargo.toml

@@ -12,7 +12,7 @@ qmp = ["qemu-display/qmp"]
 log = "0.4"
 pretty_env_logger = "0.4"
 once_cell = "1.5"
-zbus = { version = "3.0" }
+zbus = { version = "~3.3" }
 qemu-display = { path = "../qemu-display" }
 keycodemap = { path = "../keycodemap" }
 rdw = { package = "rdw4", version = "0.1", features = ["bindings"] }