There is no malware (see below commenters who have encountered similar issues).
The build of Ren'Py creates a 32 bit distribution which is erroneously identified as malware by some antiviruses. This is not unique to this game and many others using Ren'Py have had the same issue with antiviruses reporting the same false positive.
This distribution has been live for almost a year and is fully safe, but proceed (or don't!) at your discretion.