Currently there is no trigger for Google Drive, please check the following doc:
Besides, there is a similar request on Flow Ideas Forum, please vote the idea at here:
Hi SolarWill. There are Google Drive REST Apis
You could authenticate to the API and use HTTP request, GET, POST etc to acheive actions on Drive.
It's not a solution, but a workaround and maybe something you could look into.
If you are willing to take it on there are plenty of posts from the community referencing APIs and calling them that could get you started.
Here is a session from @aprildunnam at #MSFlowConf which aired last night.
I hope you find it useful.