Fix a typo in the docs for "mix release" (#8950)
Fix a typo in the docs for "mix release" (#8950)

[ci skip]
kimshrier/elixir,kelvinst/elixir,lexmag/elixir,elixir-lang/elixir,ggcampinho/elixir,michalmuskala/elixir,joshprice/elixir,lexmag/elixir,kelvinst/elixir,pedrosnk/elixir,pedrosnk/elixir,kimshrier/elixir,ggcampinho/elixir