Just a quick share as I would have been happy to come across such Zap.
I made a quick Zapier Zap which automatically create a Google Calendar event upon creating a task WITH due hour in Asana inside a given project.
You may also add / remove hours according to your timezone difference.
It should be straight forward.
The ZAP only works upon a new tasks creation and can be modified upon task updates.
Hope it will be useful for some.