Replace deprecated `set-output` command with environment file

[jongwooo]

Is your feature request related to a problem? Please describe.

In .github/workflow/issues.yaml, set-output command is deprecated and will be disabled soon.

Describe the solution you'd like

Please upgrade to using Environment Files. For more information, see: https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

Describe alternatives you've considered
N/A

Additional context
N/A

[github-actions]

Hi @jongwooo thanks for reporting!

Be sure to check out the docs while you wait for a human to take a look at this 🙂

Cheers!