First it isn't wise to post active links to suspect sites (regardless if you think they aren't) to avoid accidental exposure.
That said I don't get an alert when I visit with Avast Antivirus, so I don't know why it would cause any warning/alert in the Avast Online Security and Privacy browser extension (which I don't use).
A screenshot of the notification might be helpful, attach it to your next reply.
Reporting a Possible False Positive File or Website -
https://www.avast.com/false-positive-file-form.php.
You should get a response in a day or two.
That said I don't know if that is appropriate as it isn't the antivirus that is alerting, make the point in the Remarks that it is related to the Avast Online Security and Privacy browser extension. You could also give a link back to this topic.