update CHANGELOG

CHANGELOG.md

@@ -10,6 +10,7 @@ that users understand how the changes affect the new version.
 -->
 version 3.1.0
 ---------------------------
++ Add WDL task for smoove (lumpy) sv-caller.
 + Default threads for BWA in bwa.Kit task: 4. Samtools sort in the
   same task: 1. Output BAM compression level to 1.
 + Lima: Add missing output to parameter_meta.