-1 as I afraid it may violate "Apache Way". Microsoft is going to buy GitHub. What happens to Apache histories if one day he decided to drop GitHub data including Apache projects histories?! or decided to change usage license or payment?! and etc! However, I found it seems was legally OK in 2016 [1] BUT I think we must ask again also "general@incubator and/or community@apache and/or board rather than at legal-discuss" [1]. (at least informs them about the state of the art).
I don't think we need to worry about Microsoft buying Github at the moment and this should also not affect this discussion. If Apache becomes unhappy with github at some point in time, we can just move the code (to which github does not have any claims) someplace else.
-sebastian