Remove unused ignored entries in .gitignore (#6073)
Remove unused ignored entries in .gitignore (#6073)

/.release was removed in these two commits:
8ced611aee30a30ed6728a9ef32c0d7094f3a262
85fca3de2ecc36436e655db6afa0acf9bfa51f43

/rel/elixir was removed in this commit:
d44e8bd1f6efc54e664c28fdfc864af37e7e3129

/ebin was previously used with rebar2.
elixir-lang/elixir,joshprice/elixir,kimshrier/elixir,kimshrier/elixir,antipax/elixir,gfvcastro/elixir,kelvinst/elixir,michalmuskala/elixir,beedub/elixir,gfvcastro/elixir,ggcampinho/elixir,antipax/elixir,lexmag/elixir,lexmag/elixir,pedrosnk/elixir,beedub/elixir,kelvinst/elixir,pedrosnk/elixir,ggcampinho/elixir