Update changelog

CHANGELOG.md

@@ -11,6 +11,7 @@ that users understand how the changes affect the new version.
 
 version 5.0.0-dev
 ---------------------------
++ DeepVariant: Add an optional input for the gvcf index.
 + Samtools: `Sort` task now has `threads` in runtime instead of `1`.
 + Picard: Add parameter_meta to `SortSam`.
 + pbmm2: Add parameter_meta for `sample`.