GitHub Action: Automerge Dependabot Pull Requests

.github∕dependabot.yml

version: 2
updates:
  - package-ecosystem: "npm"
    directory: "/"
    schedule:
      interval: "daily"

.github∕workflows∕automerge.yml

on: pull_request

jobs:
  automerge:
    runs-on: ubuntu-latest
    if: github.actor == 'dependabot[bot]'
    steps:
      - uses: actions/github-script@v2
        with:
          github-token: ${{secrets.GITHUB_TOKEN}}
          script: |
            const { repository: repo, pull_request: pr } = context.payload
            github.pulls.createReview({
              owner: repo.owner.login,
              repo: repo.name,
              pull_number: pr.number,
              event: 'APPROVE'
            })
            github.pulls.merge({
              owner: repo.owner.login,
              repo: repo.name,
              pull_number: pr.number
            })