Create publishing-bot issue only for rc.0 release

[xmudrii]

What type of PR is this?

/kind bug

What this PR does / why we need it:

The publishing-bot reminder issue is supposed to be created only when we cut the rc.0 release. At the moment, it's created for any pre-release rc release, i.e. *.0-rc.*.

e.g. kubernetes/sig-release#2674 is a duplicate of kubernetes/sig-release#2669

The logic in this PR has been based on

release/cmd/krel/cmd/release_notes.go

Lines 841 to 847 in 7aef8df

	if len(tagVersion.Pre) == 2 && //nolint:gocritic // a switch case would not make it better
	tagVersion.Pre[0].String() == "alpha" &&
	tagVersion.Pre[1].VersionNum == 1 {
	startTag = util.SemverToTagString(semver.Version{
	Major: tagVersion.Major, Minor: tagVersion.Minor - 1, Patch: 0,
	})
	tagChoice = "previous minor version"

Does this PR introduce a user-facing change?

Create the publishing-bot reminder issue only when cutting `*.0-rc.0` release

/assign @saschagrunert @cpanato @puerco @Verolop
cc @kubernetes/release-engineering

[k8s-ci-robot]

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This pull-request has been approved by: cpanato, xmudrii

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