It would be great if both the core GeneratePress files and the GP Premium Plugin pack would have an “Update” option for us to click when we’re ready to update either one. Unless I missed something, the only options we have now is to (1) either let WP run the auto-updates (too risky for my taste) or (2) manually download the files and install.
GeneratePress updates are pushed out via WordPress.org, and can be found in the “Updates” or “Themes” sections of your Dashboard when an update is available.