[GR] Update gr/lessons/advanced/gen-stage.md to 1.0.2 (#2132)
[GR] Update gr/lessons/advanced/gen-stage.md to 1.0.2 (#2132)

Thanks @Kosmas !
doomspork/elixir-school,nscyclone/elixir-school,doomspork/elixir-school,doomspork/elixir-school,doomspork/elixir_school,nscyclone/elixir-school,doomspork/elixir_school,doomspork/elixir_school,nscyclone/elixir-school,nscyclone/elixir-school