chore: update config to use version

cosmic-applet-audio/src/config.rs

@@ -3,13 +3,7 @@ use cosmic::cosmic_config::{self, CosmicConfigEntry};
 use serde::{Deserialize, Serialize};
 
 #[derive(Default, Debug, Clone, Serialize, Deserialize, CosmicConfigEntry, PartialEq, Eq)]
+#[version = 1]
 pub struct AudioAppletConfig {
     pub show_media_controls_in_top_panel: bool,
 }
-
-impl AudioAppletConfig {
-    /// Returns the version of the config
-    pub fn version() -> u64 {
-        1
-    }
-}