This is a false positive as there aren't any viruses in the download, which is a known issue with Ren'py games. Here's one example from the official forums, and someone else on itch.io with the same problem on a different game. Unfortunately, it's been inconsistent in when it gets flagged, so it's been hard to troubleshoot, but we're looking into what we can do about it. The uploads on itch are the same as the ones on Steam, which passed Steam's internal checks for viruses as well.
What version of the game was it, and what antivirus software do you use?