Add option for job `requires` to be or-ed instead of and-ed

[yousefhamza]

I have a case where I want multiple a job to depend on only 1 of multiple jobs

workflows:
  version: 2
  build-test-and-generate-binary:
    jobs:
      - job1
      - job2
      - job3:
          type: approval
          requires: # Want to have the option here so that if *either* job1 *or* job2 ends, job3 will start.
            - job1
            - job2
      - job4:
          requires:
            - job3