Hackney version lock

[rodrigues]

Hi there!

I see in https://github.com/ymtszw/hipchat_elixir/blob/master/mix.exs#L37 that this package requires specifically hackney 1.6.3.

Could this version be relaxed, maybe to something like ~> 1.6.3?

Thanks 👍🏼

[ymtszw]

(Just a side note: I might consider dropping hackney dependency someday, and use erlang's default httpc for the sake of easier dependency management by users)

[ymtszw]

I will close this when I made a release with #2

[ymtszw]

Published as 0.3.0