There are no viruses, the game is 100% guaranteed safe. All games on itch are scanned with multiple anti-virus programs before release so there isn't even a chance of publising a virus.
What you are seeing is called false positive, it's when a file, most likely exe (like a game) needs to save data on disk, this behaviour is often mistakenly taken as "virus" by anti-virus programs. This issue is known to Game Maker since 2015 but nobody ever fixed it.
Other GM devs have the same issue https://forum.yoyogames.com/index.php?threads/false-positive-with-all-versions-o...
I would probably need to make installer instead of exe to avoid this false-positive warning