Checking in changes prior to tagging of version 0.23.

Changelog diff is:

diff --git a/Changes b/Changes
index e8a48f9..0059364 100644
--- a/Changes
+++ b/Changes
@@ -2,6 +2,10 @@ Revision history for Perl module Ukigumo::Client

 {{$NEXT}}

+0.23 2014-03-17T03:45:06Z
+
+    - Fix a bug that cannot create notifier instance
+
 0.22 2014-03-13T10:45:34Z

     - Support compare_url (for GitHub webhooks)