Add a new flag, similar to the flag for apply, to request server-side
apply on diff. Also add the force-conflicts flag from apply so that you
can see what happens when you re-acquire the ownership of fields.
There is currently a race-condition when diffing, where we get the
object and then run a server-side dry-run patch and compare the two
results. If something changes the object on the server between the get
and the patch, the diff is going to show unrelated changes. We can now
specify the exact revisionversion that we want to patch, and that will
return a conflict, and we can retry multiple times to get a
non-conflicting diff. Eventually (after 3 times), we diff without
checking the version and throw a warning that the diff might be
partially wrong.
We changed the code to verify that the type supports dry-run, but we've
only done it for patch, not for create, which means that people can
create objects they don't want to create. We can actually simplify the
code by moving the check much earlier in the method, which fixes all
possible bug like this.
For each object, first we verify if they have a dryRun parameter in the
openapi for the patch verb. If we can't find the object, we assume that
CRD will behave like "namespace". So we check if namespace supports
dryRun. If it does, then we verify that the resource is a CRD.
