Make .voters.yml optional

[foxted]

For private repositories, in some instances, voting only requires the majority of contributors, no matter which contributors is voting.

I would suggest making the .voters.yml optional, and automatically assume a weight of 1 for each individual voter.

[myyk]

This is a great suggestion and one I've heard before. I could imagine even making this the default in a v3 if people seem happy with it.

I'd be happy to accept a pull request that adds that, especially if the feature could have some testing for the functionality since maintenance is the most difficult part for this project.

It would also need some documentation updates to show how it works.

[myyk]

Oh to clarify this, what were you thinking as the default group of voters? Is it from the approvers of the repo or something related to the org membership? Or some % of users that have ever contributed to the repo?