Add expandable auto-generated release notes for beta and RC (non-GA) releases

[nprokopic]

What would you like to be added (User Story)?

(Coming from #9104)

As a Cluster API release team member, I would like to be create auto-generated release notes for beta and RC (non-GA) releases the same like release notes are generated for GA releases.

Detailed Description

When running make release-notes for a pre-release, instead of outputting a static text defined in the Makefile, run go run ./hack/tools/release/notes.go to generate release notes for a beta/RC release.

This requires adding support for beta and RC releases to go run ./hack/tools/release/notes.go so that (expandable) release notes are generated automatically.

Release notes for a beta/RC release must have a clear signal on top that the release is a beta/RC.

Anything else you would like to add?

This issue could be considered obsolete if Cluster API project decides to switch to Kubernetes release-notes tool. For more details see #8292.

Label(s) to be applied

/kind feature
/area release

[nprokopic]

/assign

[furkatgofurov7]

/triage accepted

[furkatgofurov7]

/priority backlog

[furkatgofurov7]

@nprokopic hey, just checking in the status here: is there any progress on this issue or do you need help with anything?

[furkatgofurov7]

/unassign @nprokopic
/help

[k8s-ci-robot]

@furkatgofurov7:
This request has been marked as needing help from a contributor.

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In response to this:

/unassign @nprokopic
/help

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.

[chandankumar4]

I'll work on this issue.
/assign