Update CHANGELOG.md.

CHANGELOG.md

@@ -10,6 +10,7 @@ that users understand how the changes affect the new version.
 -->
 version 3.1.0
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++ Samtools SortByName is now called Sort.
 + Generalize sort task to now also sort by position, instead of just read name.
 + Add CreateSequenceDictionary task to picard.
 + Add faidx task to samtools.