Checking in changes prior to tagging of version 0.22.

Changelog diff is:

diff --git a/Changes b/Changes
index 7775bd8..402cace 100644
--- a/Changes
+++ b/Changes
@@ -2,6 +2,11 @@ Revision history for Perl extension OrePAN2

 {{$NEXT}}

+0.22 2014-02-27T07:04:18Z
+
+    - Use IO::Zlib instead of PerlIO::gzip.
+      (tokuhirom)
+
 0.21 2014-02-26T09:47:32Z

     - OrePAN2::Indexer: Make temporary file in the same parition.