feature: add approve workflows action

[JesseStutler]

BackGround

When contributors from outside contribute their first PR to volcano repo, the repo admin has to click the approve and run button to run the CI, even the approvers don't have the permissions to run the CIs when they are not repo admin. And the volcano-bot cannot automatically run CIs, because the bot uses prow as the testing framework. Currently prow uses k8s' own testing framework, and its integration with github workflow is not so good. So, inspired by this issue: kubernetes-sigs/prow#194, and this config: https://github.com/kubernetes-sigs/cluster-api/blob/main/.github/workflows/pr-gh-workflow-approve.yaml, we can add a action, when there is ok-to-test label in this first PR(which is already reviewed by reviewers), this github workflow can be ran to call other workflows. Therefore, approvers can have the right to run CIs, not only the repo admin.

Testing

Test-1

Add ok-to-test label, Approve Workflow action can run:

And other workflows can run subsequently:

Test-2

Tag other labels, other workflows can't run, and Approve Workflows action is skipped

Test-3

PR to non release-** and master branch, ok-to-test label is useless, only PR to release-** and master branch is useful.

[volcano-sh-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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Needs approval from an approver in each of these files:

• OWNERS

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[JesseStutler]

/assign @Monokaix

[hwdef]

Who has permission to add ok-to-test label?