Retinafy Github/Harvest badges on the public site

[tjschuck]

@harvesthq/designers Super low priority, but if anyone wants to take a crack at a small win: on the Chosen site, that upper right image is very not-retina.

Here's the file itself: https://github.com/harvesthq/chosen/blob/master/public/docsupport/oss-credit.png — no meaningful history to help you, but it looks like it was added by Ken, but I assume it was probably created by @mlettini who might have the source lying around somewhere?