Only add missing number of reviewers (if necessary)

[bobek]

Is your feature request related to a problem? Please describe.
We have numberOfReviewers set to 2. Everything works as expected, bot will always add 2 new reviewers.

Describe the solution you'd like
I would like to be able to instruct bot not to add more then missing count of reviewers for PRs where I've already selected reviewers manually. I would expect, that numberOfReviewers behaves as a desired number of reviewers on the PR. For example:

• PR has 0 reviewers -> bot will add 2
• PR has 1 reviewer -> bot will add 1
• PR has 2 and more reviewers -> bot will not add any new one

Alternatively we can introduce a new setting, something like maximumNumberOfReviewers for gating PRs which will get ignored by bot.

[hnandiwada]

I would love to see this implemented! I often have a specific reviewer in mind that I'd like to assign, and often find myself removing the bot's addition.