Add Nathan and Patrick as code owners

[pitag-ha]

Thanks a lot, @NathanReb and @patricoferris, for pretty much having taken over the maintenance! :heart:

[NathanReb]

Looks good to me but Github seems to complain about @patricoferris not having the right access level to the repo or something along those lines. It might be that Patrick has to accept the maintainer invitation first I guess.

[patricoferris]

Just accepted!