Hi James,
You should update your Avast signature database. Avast assured today us that detection is no more:
Hello,
Thank you for reporting this false positive.
Our virus specialists have now cleared its reputation in our database.
With URLs this change should be instant, but it might take up to 24 hours with files.
For future reference you might also find the following article to be useful: Avast Clean Guidelines.
Best regards,
Avast Customer Care