update changelog

debian/changelog

+ruby-gnuplot (2.4.1-1) unstable; urgency=low
+
+  * New upstream version 
+  * Add myself to Uploaders:
+  * Bump Standards-Version to 3.9.3 (no changes needed)
+  * Update copyright to DEP-5 copyright-format/1.0
+  * Refresh fix-tests.patch
+  * Clean examples/sine_wave.gif generated from tests
+  * Override lintian warning about duplicate description of transitional
+    packages
+  * Set priority of transitional packages to extra
+  * Replace Conflicts: by Breaks: for relation with transitional packages
+
+ -- Cédric Boutillier <cedric.boutillier@gmail.com>  Mon, 11 Jun 2012 00:09:08 +0200
+
 ruby-gnuplot (2.3.6-1) unstable; urgency=low
 
   * Switch to gem2deb-based packaging.