Do not propagate Helm release Secrets

[mochizuki875]

What type of PR is this?:

/kind feature
/kind documentation

What this PR does / why we need it:

Added Secrets of Type helm.sh/release.v1 to built-in exceptions.

Tested:

Added new unit test for my change; verified that the test passed.

Which issue(s) this PR fixes:

#241

Special notes for your reviewer:

This PR includes documentation fix to add this feature to Built-in exceptions section.
In this section, I wrote Planned for future version: because I'm not sure when this feature will be released.
If you have any plan, please tell me and I'll rewite the sentence.

[k8s-ci-robot]

Hi @mochizuki875. Thanks for your PR.

I'm waiting for a kubernetes-sigs 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.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[mochizuki875]

/assign @adrianludwin

[adrianludwin]

/lgtm
/approve
/ok-to-test

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: adrianludwin, iuriaranda, mochizuki875

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