Update changelog with samtools change

CHANGELOG.md

@@ -9,6 +9,8 @@ that users understand how the changes affect the new version.
 -->
 version 5.1.0-dev
 ---------------------------
++ Update samtools image to version 1.16.
++ Add targetsFile input for samtools View.
 + Mateclever's runtime attribute defaults were changed to:
   + memory: `"250GiB"`
   + timeMinutes: `2880`