codefix: add VoiceAPIVersion constant to DiscordConfig

src/Discord.Net.Core/DiscordConfig.cs

@@ -5,6 +5,7 @@ namespace Discord
     public class DiscordConfig
     {
         public const int APIVersion = 6;
+        public const int VoiceAPIVersion = 3;
         public static string Version { get; } =
             typeof(DiscordConfig).GetTypeInfo().Assembly.GetCustomAttribute<AssemblyInformationalVersionAttribute>()?.InformationalVersion ??
             typeof(DiscordConfig).GetTypeInfo().Assembly.GetName().Version.ToString(3) ??

src/Discord.Net.WebSocket/Audio/AudioClient.cs

@@ -107,7 +107,7 @@ namespace Discord.Audio
         private async Task OnConnectingAsync()
         {
             await _audioLogger.DebugAsync("Connecting ApiClient").ConfigureAwait(false);
-            await ApiClient.ConnectAsync("wss://" + _url + "?v=3").ConfigureAwait(false);
+            await ApiClient.ConnectAsync("wss://" + _url + "?v=" + DiscordConfig.VoiceAPIVersion).ConfigureAwait(false);
             await _audioLogger.DebugAsync("Listening on port " + ApiClient.UdpPort).ConfigureAwait(false);
             await _audioLogger.DebugAsync("Sending Identity").ConfigureAwait(false);
             await ApiClient.SendIdentityAsync(_userId, _sessionId, _token).ConfigureAwait(false);