Obviously not what you're looking for, but Gitlab does have a "Mirror repo to Github" feature.
Oh yeah, but that would mean I have to copy or mirror all of my gitlab repos to github. I will settle for the commit log printed on a simple coffee mug for the moment :)
I guess someone can create a "free and open" version of that, generate the STL and use a similar provider as above.
3D printing yourself and using a cheapo CNC can also do the trick... I wonder how hard it is to programmatically generate the STL yourself.