exclude terraform.tfstate backups in .gitignore

[rptaylor]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:
Newer versions of Terraform use timestamps in the backup name, e.g. terraform.tfstate.1614728479.backup

Special notes for your reviewer:

Does this PR introduce a user-facing change?: NONE

Exclude terraform.tfstate backups in .gitignore

[k8s-ci-robot]

Hi @rptaylor. 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.

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[floryut]

@rptaylor Thank you for the PR 👍
/ok-to-test

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: floryut, rptaylor

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[k8s-triage-robot]

Unknown CLA label state. Rechecking for CLA labels.

Send feedback to sig-contributor-experience at kubernetes/community.

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/easycla

[MrFreezeex]

Looks good thanks :D, CI is not very happy though you should probably try to rebase to rekick it...
/lgtm

[rptaylor]

Okay thanks. I'm not sure what is wrong with the CI but there have been no commits since yesterday so there is nothing to rebase.

[MrFreezeex]

You can amend your last commit without changing anything and push force it will also rekick the ci

[yankay]

Thanks @rptaylor
/lgtm