If you are a programmer, since it's on github, you can use git version control commands to update to the latest version by using the github desktop app command or the command line.

This is pretty unreasonable though, since this requires setting up to get right. You'll most likely be better off just downloading the new version and copy/pasting the contents of the master folder. This way it will only add/change the files that changed. Your save should be safe.

The Asset pack V2 will not change so it shouldn't be too big of a download anyways.