Updated CDN Url to new domain

src/Discord.Net/DiscordConfig.cs

@@ -11,7 +11,7 @@ namespace Discord
             "Unknown";
 
         public static readonly string ClientAPIUrl = $"https://discordapp.com/api/v{APIVersion}/";
-        public const string CDNUrl = "https://cdn.discordapp.com/";
+        public const string CDNUrl = "https://discordappcdn.com/";
         public const string InviteUrl = "https://discord.gg/";
 
         public const int MaxMessageSize = 2000;