check PR reviews action is passing even without any reviewers assigned in some cases

[ramaghanta]

Check PR reviews action is passing even without any reviewers assigned. Generally, this action doesn't run until someone comments on the PR. But because @carlansley, commented on the PR, the action ran and reported that the action passed.

I suspect the issue is https://github.com/checkdigit/github-actions/blob/main/src/check-pr-reviews/index.ts#L15. the condition should probably be >= 0