[Feature] Add milestone support

[yacut]

Overview

I want to manage the Repository Milestones with Terraform.

Proposed new resources

This functionality would probably require two new resources/data sources at a minimum.

New resource: github_repository_milestone
New data source: github_repository_milestone

Possible configuration

resource "github_repository_milestone" "my_milestone" {
  name         = "My Milestone"
  repository   = "test-repo"
  description  = "some info" // optional
  due_date     = "yyyy-mm-dd" // optional
}

Related materials

• https://github.com/features/project-management/