Missing unzip command

Signed-off-by: Marco Marinello <me@marcomarinello.it>
2 jobs for buster in 13 minutes and 34 seconds (queued for 20 seconds)
Status Job ID Name Coverage
  Clonezilla
passed #99
rebuild-squashfs

00:04:20

 
  Packaging
passed #100
build-buster

00:09:14