Don't use `Mix.shell().cmd/1` for running tasks after the igniter runs

[Zach Daniel]

For some reason, we couldn't get Mix.Task.run to work. Tried everything we could think of and ultimately fell back to

igniter.tasks
|> Enum.each(fn {task, args} ->
  Mix.shell().cmd("mix #{task} #{Enum.join(args, " ")}")
end)

[Zach Daniel]

There is no good way out of this actually :)