Update CI builds: add OTP 20.1 (#6940)
Update CI builds: add OTP 20.1 (#6940)


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