For those interested: Github App Thread is here
and I see that makes sense (pointing to an network drive).
If I’m understanding your setup to having the our_ribbon.extension folder as part of the repo, then I think you need something like
--dest="C:\pyRevit-Master\extensions"
I will have to try this to see - it may work, but not positive (since I think the issue is more on grabbing the correct location from the repo than it is sending to the correct destination)