Rebase workflow for Github action

rebase.yml

name: Automatic Rebase

on:
  issue_comment:
    types: [created]

jobs:
  rebase:
    name: Rebase
    if: github.event.issue.pull_request != '' && contains(github.event.comment.body, '/rebase')
    runs-on: ubuntu-latest

    steps:
      - name: Checkout the repository
        uses: actions/checkout@v2
        with:
          token: ${{ secrets.GITHUB_TOKEN }}
          fetch-depth: 0 # otherwise, you will fail to push refs to dest repo

      - name: Rebase automatically
        uses: cirrus-actions/rebase@1.2
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}