Fix: skipping merge based on PR label

[devidasjadhav]

Which problem is this PR solving?

Resolves #4799

Description of the changes

• Added github action to skip based on PR label.

How was this change tested?

• tested it on my repository in main branch. which skipped this test.
  I have deleted that repo.

Checklist

• [ x] I have read https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
• [ x] I have signed all commits
• I have added unit tests for the new functionality
• I have run lint and test steps successfully
  • for jaeger: make lint test
  • for jaeger-ui: yarn lint and yarn test

[devidasjadhav]

I have fixed first task. i.e. Add a GitHub Action that will verify that a PR has a specific categorization label before it can be merged. We already have a bunch of those labels changelog:*** labels

I can change label if needed.
Please suggest label. I didn't spot changelog: lable in PR's.

[yurishkuro]

• this does not resolve [Feature]: (Re)Introduce changelog-related labels and require them for PRs #4799
• we don't use Do Not Merge label today. I don't see a particular value in it:
  • if PR author does not want PR merged, they can turn it into Draft or add WIP to the title
  • if maintainers don't want PR merged by accident, then can request changes on it via Approvals

[yurishkuro]

Add a GitHub Action that will verify that a PR has a specific categorization label before it can be merged.

This means the PR must contain a label of the form /^changelog:.*/

[yurishkuro]

The ticket has been addressed in other PRs.