1) the .net version has a couple of very high authority links, namely from theregister and thenewstack (both of which have had lots of engagement).
I highly doubt it would have ranked without those links.
2) its only been a week. Give Google time to understand which pages should rank higher.
3) Google is biased towards sites that cover a topic earlier than others.
I’ve seen pages that are still top 3 for a particular competitive query years later, simply because they were one of the first to write about it.
Suggestions: give it time. Meanwhile I would recommend linking to your website rather than your github everywhere you mention it, to give it a boost