docs: add cypress github action examples

[MikeMcC399]

Situation

This repo contains no examples of using Cypress Docker images with the Cypress JavaScript GitHub Action cypress-io/github-action.

The included/README links to https://github.com/cypress-io/github-action#docker-image where there is only an example with cypress/browsers:latest. Examples for cypress/base and cypress/included are missing.

Change

1. Add a workflow example-cypress-github-action.yml to run against the examples, showing each of the browsers: Electron, Chrome, Edge and Firefox. The workflow is triggered only on manual demand with workflow_dispatch.
2. Add a link into README > Examples

[cypress-app-bot]

• Create a Draft Pull Request if your PR is not ready for review. Mark the PR as Ready for Review when you're ready for a Cypress team member to review the PR.

[MikeMcC399]

Preview

• Workflow log https://github.com/MikeMcC399/cypress-docker-images/actions/workflows/example-cypress-github-action.yml
• https://github.com/MikeMcC399/cypress-docker-images/tree/add-gha-examples/README.md#examples