add "--dry-run" option for push

[jgangemi]

it would be great to be able to detect if the version of the chart as not been changed as part of PR validation instead of waiting until release.

this option would indicate if a chart upload would fail due to the version not being changed.

[hypnoglow]

Hi @jgangemi , thanks for your interest.

So, you mean, you want to check if such version already exists in the repository without triggering an error from helm s3 push, right?

Is #41 related?

[jgangemi]

that is correct. that way i can ensure the version was changed as part of the ci/pull-request check instead of waiting for release.

i don't think this is related to #41 - that request is to push the files and not error out if the version exists, whereas i want to know if it will fail w/o actually pushing.