First, I’m an Avast user and not an Avast Team member.
Possible False Positive - New location to report both a False Positive and or a False Negative (for File or URL) - Choose Your Sample Submission Type | Avast - You won’t get a direct response but it should be analysed within 48 hours, if found to be false it will be removed.
There are sites that can also check a site link and or file upload.
https://www.virustotal.com/ this currently give it zero hits, but Avast’s webshield is a live scan (not on-demand).