Update CHANGELOG

CHANGELOG

-minerva (12.3.1~beta.1) unstable; urgency=low
+minerva (13.1.0~beta.1) unstable; urgency=low
   * Small improvement: model_name renamed to map_name in data overlay columns 
     (#827)
   * Small improvement: name, type, reference_genome_type and 
@@ -34,6 +34,8 @@ minerva (12.3.1~beta.1) unstable; urgency=low
   * Bug fix: asynchronous cals on showing/hiding data overlays might cause 
     problems due to network latency (#830)
 
+ -- Piotr Gawron <piotr.gawron@uni.lu>  Fri, 7 Jun 2019 17:00:00 +0200
+
 minerva (13.1.0~beta.0) unstable; urgency=low
   * Feature: annotators are more flexible - you can define set of input and
     outputs used by annotator (#617)