waybar: Use myxer as a graphical audio mixer

modules/programs/waybar/default.nix

@@ -44,6 +44,9 @@
               on-click = "${pkgs.wlogout}/bin/wlogout";
               tooltip = "false";
             };
+            "pulseaudio" = {
+              on-click = "${pkgs.stable.myxer}/bin/myxer";
+            };
           };
         }
       ];