feat: Add required_workflows to github_organization_ruleset

[relusc]

Resolves #1970

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This adds a new field required_workflows to github_organization_ruleset to be able to specify workflows that must pass.

Example:

data "github_repository" "workflow_repo" {
    name = "workflow_repo"
}

resource "github_organization_ruleset" "ruleset" {
    name        = "example"
    target      = "branch"
    enforcement = "active"

    rules {
      required_workflows {
        required_workflow {
          repository_id = data.github_repository.workflow_repo.repo_id
          path          = "path/to/workflow.yaml"
          ref           = "main"
        }

        required_workflow {
          repository_id = data.github_repository.workflow_repo.repo_id
          path          = "path/to/second_workflow.yaml"
          ref           = "main"
        }
      }
    }
}

Pull request checklist

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)

Does this introduce a breaking change?

• Yes
• No

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[nickfloyd]

Thanks for the contributions here @relusc! ❤️