Update to manifest v3

[professorxavi]

with v2 being deprecated this will need to be updated at some point. If that something that is being looked into at all? I can take a stab at it but I want to make sure before I dive in.

[BurtHarris]

Great question. I'm just beginning to look into this extension, but I don't know if this repro is being maintained actively. I'd love to be wrong about that. Anybody?

[professorxavi]

I decided to use this as a base for the specific use I had. When I get that working fully on v3, I'll port the necessary changes and open a pr if someone doesn't beat me to it.