update changelog for v4.0.5

CHANGELOG.md

@@ -3,8 +3,17 @@
 Each release usually includes various fixes and improvements.
 The most noteworthy of these, as well as any features and breaking changes, are listed here.
 
+## v4.0.5
+* Updated Lavaplayer to [`2.1.2`](https://github.com/lavalink-devs/lavaplayer/releases/tag/2.1.2)
+* Updated Koe to [`2.0.1`](https://github.com/KyokoBot/koe/releases/tag/2.0.1) (fixes the `IndexOutOfBoundsException` when playing a YouTube track)
+* Added option to enable [Nico](https://www.nicovideo.jp/) source
+* Expose Lavalink sessions to plugins via the `ISocketServer` interface
+
+> [!WARNING]
+> The default Youtube source is now deprecated and won't receive further updates. Please use https://github.com/lavalink-devs/youtube-source#plugin instead.
+
 ## v4.0.4
-* Update Lavaplayer to `2.1.1`
+* Update Lavaplayer to [`2.1.1`](https://github.com/lavalink-devs/lavaplayer/releases/tag/2.1.1)
 
 ## v4.0.3
 * Fixed plugins not registering (introduced in [`4.0.2`](https://github.com/lavalink-devs/Lavalink/releases/tag/4.0.2))