Fix #812: Write a trailing newline character to the Mix lockfile.
Fix #812: Write a trailing newline character to the Mix lockfile.

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