Update changelog for OpenZFS 2.2.0 release

This commit updates changelog for native Debian packages for
OpenZFS 2.2.0 release.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Umer Saleem <usaleem@ixsystems.com>
Closes #15104

contrib/debian/changelog

@@ -1,3 +1,9 @@
+openzfs-linux (2.2.0-0) unstable; urgency=low
+
+  * OpenZFS 2.2.0 is tagged.
+
+ -- Umer Saleem <usaleem@ixsystems.com>  Tue, 25 Jul 2023 15:00:00 +0500
+
 openzfs-linux (2.1.99-1) unstable; urgency=low
 
   * Integrate minimally modified Debian packaging from ZFS on Linux