You can update an Asset Store package in the Package Manager window:
Open the Package Manager window and select My Assets from the Packages drop-down menu.
An arrow indicator appears next to any Asset Store packages that have updates available.
To see the most recent updates for your Asset Store packages, sort the list by Updated date from latest to oldest.
In the list of packages, click the expander icon to the left of the Asset Store package’s name.
The newer version displays Update Available and the installed version displays Currently Downloaded.
Select the new version for the current Asset Store package and see the details specific to that version in the details view.
Click the Update button.
When the progress bar finishes, the new Asset Store package version information appears in the details view, and is immediately available.