Update ink! requirements to 4.2.0

[ascjones]

No description provided.

[athei]

I wonder if we provide much value by bumping this on every minor. Since new projects will go to the newest minor automatically anyways. So we could just set it to "4" and save us some chores.

[ascjones]

I wonder if we provide much value by bumping this on every minor. Since new projects will go to the newest minor automatically anyways. So we could just set it to "4" and save us some chores.

It is not always necessary, but in this case I believe it might be since it includes some metadata additions e.g. use-ink/ink#1741. So in this case e.g. we want to guarantee that the minimum version is 4.2 so that it includes those changes. It might be possible if another dependency has "=4.0 for ink then it could pull in an older version still.