Solution: YAML Syntax

name: YAML Syntax
on:
  workflow_dispatch:
  push:
    branches:
      - main
jobs:
  initial:
    runs-on: ubuntu-latest
    steps:
      - run: echo "This job will be run first."

  fanout1:
    runs-on: ubuntu-latest
    needs: initial
    steps:
      - run: echo "This job will run after the initial job, in parallel with fanout2."

  fanout2:
    runs-on: ubuntu-latest
    needs: initial
    steps:
      - run: echo "This job will run after the initial job, in parallel with fanout1."

  fanout3:
    runs-on: ubuntu-latest
    needs: fanout1
    steps:
      - run: echo "This job will run after the initial job, in parallel with fanout2."

  fanin:
    runs-on: ubuntu-latest
    needs: [fanout1, fanout2]
    steps:
      - run: echo "This job will run after fanout1 and fanout2 have finished."

  build:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        configuration: [debug, release]
    steps:
      - run: echo "This job builds the cofiguration $."

  test:
    runs-on: ubuntu-latest
    needs: build
    steps:
      - run: echo "This job will be run after the build job."

  ring01:
    runs-on: ubuntu-latest
    needs: test
    steps:
      - run: echo "This job will be run after the test job."

  ring02:
    runs-on: macos-latest
    needs: test
    steps:
      - run: echo "This job will be run after the test job."

  ring03:
    runs-on: ubuntu-latest
    needs: test
    steps:
      - run: echo "This job will be run after the test job."

  ring04:
    runs-on: ubuntu-latest
    needs: [ring01, ring02, ring03]
    steps:
      - run: echo "This job will be run after the ring01,ring02,ring03 jobs."

  prod:
    runs-on: ubuntu-latest
    needs: [ring04]
    steps:
      - run: echo "This job will be run after the ring04 job."