Enable wrapping k8s_objects diff exit codes

[irlevesque]

Fixes: https://github.com/bazelbuild/rules_k8s/issues/679

This diff proposes one strategy we could take to wrapping the command execution of the kubectl diffs in order to address the above issue.

[k8s-ci-robot]

Hi @irlevesque. Thanks for your PR.

I'm waiting for a bazelbuild member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[chases2]

/ok-to-test

This looks like an acceptable option to me. Please be sure to:

• Sign the CLA; the output to the failing presubmit provides instructions
• Squash your 3 commits together into one

[irlevesque]

@chases2 all set, thanks!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: chases2, irlevesque

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