add changelog and fix slider outline

changes/changelog.d/318.enhancement

+Make some space for the volume slider to allow precise control (#318)

front/src/components/audio/Player.vue

@@ -421,6 +421,9 @@ export default {
     background: white;
     opacity: 0.3;
   }
+  input[type=range]::-moz-focus-outer {
+    border: 0;
+  }
   input[type=range]::-moz-range-thumb {
     background: white;
     cursor: pointer;