I don't think so, no.
Leaving aside the fact that I don't want to do that:
They've quite sensibly vendored my library, so I'd have to hope they pull in updates without checking the code changes: since it's such a tiny library (excluding tests but including fairly extensive comments, it's less than 100 lines of quite readable code) I don't think it'd be easy to get it past their code review system if I tried to sneak in enough code to take down entire companies.
Also, my GitHub account is tied to my real-world identity, so I'd probably be in a lot of trouble if I somehow succeeded.