k8s image content from PRs: Fix id in job step

[yuumasato]

Description:

• Assign an explicit id to the step which the output value comes from.
• Renames shell variable name from pr-number to pr_number to avoid issues in step.run's shell environment.

Rationale:

• The output pr-number is empty when used in container-main job.

  • Ref: https://docs.github.com/en/actions/using-jobs/defining-outputs-for-jobs

• Hopefully fixes runs Kubernetes content image for PR

Review Hints:

• Needs to be merged to take effect.
• The workflow_run always executes what is on the master branch.

[github-actions]

Start a new ephemeral environment with changes proposed in this pull request:

Fedora Environment

Oracle Linux 8 Environment

[codeclimate]

Code Climate has analyzed commit e24b49e and detected 0 issues on this pull request.

The test coverage on the diff in this pull request is 100.0% (50% is the threshold).

This pull request will bring the total coverage in the repository to 58.3% (0.0% change).

View more on Code Climate.

[rhmdnd]

/lgtm