update cabal dependencies for http-conduit 1.2.6
update cabal dependencies for http-conduit 1.2.6

Needed to add a dep on conduit to get Control.Monad.Trans.Resource.

Note: I kept the very tight versioned dependency, but I don't know that it's
correct. 1.2.5 should still work too, I guess.

jwiegley/github,jwiegley/github