scratch-www/.github/workflows/main.yml

name: Create release branch and PRs

# Controls when the action will run. 
on:
  # Allows you to run this workflow manually from the Actions tab
  workflow_dispatch:

# A workflow run is made up of one or more jobs that can run sequentially or in parallel
jobs:
  # This workflow contains a single job called "build"
  build:
    # The type of runner that the job will run on
    runs-on: ubuntu-latest

    # Steps represent a sequence of tasks that will be executed as part of the job
    steps:
      # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
      - name: Checkout master
        uses: actions/checkout@v2
        with:
          fetch-depth: 0
          ref: master
      - name: Set output variables
        id: vars
        run: |
          echo ::set-output name=branch::"release/$(date +%Y-%m-%d)"          
      - name: Create release branch and merge develop
        run: |
          git config --global user.email "${{ github.actor }}@users.noreply.github.com"
          git config --global user.name "${{ github.actor }}"
          git checkout -b ${{ steps.vars.outputs.branch }}
          git merge origin/develop
          git push --set-upstream origin ${{ steps.vars.outputs.branch }}          
      - name: Develop PR
        uses: repo-sync/pull-request@v2
        with:
          source_branch: ${{ steps.vars.outputs.branch }}
          destination_branch: develop
          pr_title: "[Develop] ${{ steps.vars.outputs.branch }}"
          github_token: ${{ secrets.GITHUB_TOKEN }}
          pr_allow_empty: true
      - name: Master PR
        uses: repo-sync/pull-request@v2
        with:
          source_branch: ${{ steps.vars.outputs.branch }}
          destination_branch: master
          pr_title: "[Master] ${{ steps.vars.outputs.branch }}"
          github_token: ${{ secrets.GITHUB_TOKEN }}
          pr_allow_empty: true