I have an older exposure trace. Really nice light for all year round, good day flash that lasts a good while, and in a pinch can be used to illuminate the road(would suggest something brighter for longer rides though).
Only downside is the charger is usb micro on mine, but it has been updated to USB C now.
https://www.exposurelights.com/products/boost-daybright-mk2-gun-metal-black
Yea, so depending on the version you go for, you just need on of the go pro mounts
The boost that I linked is this one - https://www.exposurelights.com/products/go-pro-fitting-light-clip
The slightly cheaper Trace(it is only 150 lumens) is this one - https://www.exposurelights.com/products/trace-action-mount-clip