'set-output' change to $GITHUB_OUTPUT

This action is great! thank you =) 
however, it does provide a warning "the `set-output` command is deprecated and will be disabled soon. 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/"

would be great to have this updated. thanks