Both those packages are used by nunomaduro/collision which is a dependency of the Laravel framework. You can't really do anything about this at this point. The nunomaduro/collision needs to be updated with the new dependencies or updated dependencies.
Also, it's a warning, so you shouldn't be scared about it at all. Everything still works ;)
This isn't an acceptable answer. The standard at my shop is that all composer updates should run clean, without errors or warnings. I cannot confirm that our Laravel development is free of bugs as long as composer is throwing warnings.
@jbnv That should indeed be a better approach. However, you don't always have this in the hand. This is now a package that is 4th inline based on Laravel dependencies. People are already taking action against it. That's why I showed the link of the tweet.