[BUG] `set-output` being deprecated

[cloin]

Version

redhat-actions/push-to-registry@v2

Describe the bug

Summary page for workflows utilizing this action report that this extension relies on set-output which will be deprecated end of May 2023: https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

Steps to reproduce, workflow links, screenshots

https://github.com/redhat-actions/push-to-registry/actions/runs/3484685840/jobs/5829502604#step:5:143