docs: add user parameter info to main readme

[MikeMcC399]

Issue

Currently only the included/README refers to the user parameter to run a Cypress Docker image as container.

Older Docker images fail to run in GitHub Actions if options: --user 1001 is not applied. Since it is not mandatory to use the Cypress JavaScript GitHub Action, there is a gap in the documentation when a GitHub Actions workflow is used without the Cypress JavaScript GitHub Action.

Change

Add information about the user parameter information to the main README document. Mention the non-root node user added to base, browsers and included images.

Include links to Docker documentation.

Add the instruction options: --user 1001 for general GitHub Actions usage.

[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

https://github.com/MikeMcC399/cypress-docker-images/blob/user-parameter/README.md#user