Adds PATCH Variable to Release Script

[danehans]

Adds a PATCH variable to the release script since it's missing and required to following the release workflow.

What type of PR is this?
/kind bug

What this PR does / why we need it:

The PATCH env var is set by the .github/ISSUE_TEMPLATE/new-release.md release workflow, but is not consumed by the release script. This causes the patch release to end in .0 instead of the applicable patch release.

Which issue(s) this PR fixes:

N/A

Does this PR introduce a user-facing change?:

NONE

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: danehans

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[danehans]

/backport to the release-1.0 branch

[kfswain]

/lgtm