You can't directly update someone else's package. You need to be added as a contributor to that package. I would follow these steps:
Update source and create a pull request
As you have found, the source for the project is on GitHub. You can update that and make a pull request. At the same time you can request the author update the package on the marketplace.
Locate the author on Sitecore Slack
The package says that NTT Data in the author of the package with a single checkin by Anton Setiadi. Using Sitecore Slack you can reach out to the authors and ask to be added as a contributor.
With quick scan of Linked In, I have found several users that work at NTT and also are on Sitecore Slack. You just need to locate the original author and then get authorized to update it.