feat: start several services in parallel

[bahmutov]

When you need to start webserver and API for example. Separate commands with comma

- name: Cypress tests
  uses: cypress-io/github-action@v2
  with:
    start: npm run api, npm run web
    # for now only a single URL can be waited on
    wait-on: 'http://localhost:3050' 

• for Run cypress tests in github actions, running up front-end and back-end http servers. #128

For now wait for the longest starting process

[github-actions]

🎉 This PR is included in version 2.4.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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