Add support for deployment_status events to github action

[carbonrobot]

Support the deployment_status event type for Github Actions.

This allows consumers to support running Playwright or Cypress tests after a deployment is complete to a third party platform such as Vercel when using the action in the same workflow file.

Fixes #647

Example Configuration

The following configuration currently exits with an error for unsupported event type. This PR fixes the error.

name: Chromatic

on:
  deployment_status:
  
jobs:
  playwright:
    container:
      image: mcr.microsoft.com/playwright:v1.49.0-jammy
    steps:
      - uses: actions/checkout@v4
      
      - name: Run Playwright Tests
        run: npx playwright test
        env:
          PLAYWRIGHT_TEST_BASE_URL: ${{ github.event.deployment_status.target_url }}
          
      - uses: actions/upload-artifact@v4
        if: always()
        with:
          name: playwright-results
          path: ./playwright-report
          retention-days: 30

  chromatic:
    name: Run Chromatic
    needs: playwright
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4 
      
      - uses: actions/download-artifact@v4
        with:
          path: ${{ github.workspace }}
          
      - name: Chromatic
        uses: chromaui/action@latest
        with:
          playwright: true
          projectToken: ${{ secrets.CHROMATIC_PROJECT_TOKEN }}

[carbonrobot]

Currently blocked by the same problem with deployment_status missing the branch ref as describe in actions/cache#319; but exploring workarounds.