release(0.2.4): update version number before release.

Author: SkyzohKey

src/Ricin.vala

@@ -2,7 +2,7 @@ public class Ricin.Ricin : Gtk.Application {
   const string GETTEXT_PACKAGE = "ricin";
   public static const string APP_NAME = "Ricin";
   public static const string APP_SUMMARY = "<b>Ricin</b> aims to be a <i>secure, lightweight, hackable and fully-customizable</i> chat client using the awesome and open-source <b>ToxCore</b> library.";
-  public static const string APP_VERSION = "0.2.3";
+  public static const string APP_VERSION = "0.2.4";
   public static const string RES_BASE_PATH = "/chat/tox/ricin/";
   public static const string ICON_PATH = RES_BASE_PATH + "images/icons/ricin.svg";