Currently you can't update packages with umake. Here's a link to the closed github issue How to update installed software?#122. As mentionned you only need to remove the package and reinstall it like this.
umake --remove <type> <package> && umake <type> <package>
For example, if you know that idea shoul be reinstalled, type:
umake --remove ide idea && umake ide idea
So I was lookong for a solution to update all my umake packages.