Automatic merge from submit-queue (batch tested with PRs 57324, 56931, 57000, 57150, 56965). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
allow convert to default on a per object basis
`kubetl convert` needs to distinguish between cases where a user specifies a version (use this at all cost) and cases where it doesn't (for each object, find the best version to convert to). This allows that to happen.