Readers who want to skip the clean up can edit these scripts; it seems
fair to assume that a reader who wants that would know how to edit a
shell script and delete lines from it.
Given that Pod Security Admission has been beta and then generally
available for a while, assume that kind gives the reader a cluster than
includes this feature.
The kubectl tool includes a client for fetching manifests using HTTP,
and we usually rely on that for tutorials. Switch to an approach where
we don't create a manifest on the filesystem and then apply that.