Add GitLab Pipeline documentation for `cypress/included`

[MikeMcC399]

What would you like?

Add documentation for the usage of cypress/included in a GitLab Pipeline. The entrypoint must be overridden in this case, for example:

  image:
    name: cypress/included:13.15.0
    entrypoint: [""]

The GitLab documentation Override the entrypoint of an image describes how to do this.

Why is this needed?

If a cypress/included image is used in a GitLab Pipeline without specifying an entrypoint, then the ENTRYPOINT from

cypress-docker-images/factory/Dockerfile

Lines 10 to 12 in 5a1e878

	FROM cypress/factory:${FACTORY_VERSION} AS included_image
	ENTRYPOINT ["cypress", "run"]

is used. This leads to an error message in the GitLab Pipeline similar to the following and a Pipeline failure:

Executing "step_script" stage of the job script
00:03
Using docker image sha256:045bd22a336eda152e1d83241ee15041ad48260bacef238c961093e11bc7a37f for cypress/included:13.15.0 with digest cypress/included@sha256:962fea580e73b931471105137d3b4e5a80bc007f57bfa8582b6f2bc3ee1a081b ...
[STARTED] Task without title.
[SUCCESS] Task without title.
Cypress encountered an error while parsing the argument: --config
You passed:
if [ -x /usr/local/bin/bash ]; then
	exec /usr/local/bin/bash
elif [ -x /usr/bin/bash ]; then
	exec /usr/bin/bash
elif [ -x /bin/bash ]; then
	exec /bin/bash
elif [ -x /usr/local/bin/sh ]; then
	exec /usr/local/bin/sh
elif [ -x /usr/bin/sh ]; then
	exec /usr/bin/sh
elif [ -x /bin/sh ]; then
	exec /bin/sh
elif [ -x /busybox/sh ]; then
	exec /busybox/sh
else
	echo shell not found
	exit 1
fi
The error was: Cannot parse as valid JSON
Cleaning up project directory and file based variables
00:01
ERROR: Job failed: exit code 1

This repo's documentation contains no specific instructions for using Cypress Docker images in GitLab Pipelines.

The Cypress GitLab CI documentation examples use cypress/browsers images only and do not cover the special treatment necessary for using cypress/included Docker images in a GitLab Pipeline.