Add Mix to changelog
Add Mix to changelog

beedub/elixir,joshprice/elixir,kelvinst/elixir,kimshrier/elixir,michalmuskala/elixir,elixir-lang/elixir,antipax/elixir,pedrosnk/elixir,ggcampinho/elixir,gfvcastro/elixir,gfvcastro/elixir,ggcampinho/elixir,beedub/elixir,lexmag/elixir,lexmag/elixir,pedrosnk/elixir,kimshrier/elixir,antipax/elixir,kelvinst/elixir