docs: factory version bump description

[MikeMcC399]

Issue

CONTRIBUTING > Releasing a new factory version specifies releasing a new cypress/factory version after changes to factory.Dockerfile or installScripts. It does not mention changes to the factory/.env file.

In practice, changes to the following parameters in the factory/.env file have prompted bumping the FACTORY_VERSION and recording it in the factory/CHANGELOG:

• BASE_IMAGE
• FACTORY_DEFAULT_NODE_VERSION
• YARN_VERSION

Changes to the following parameters have not caused FACTORY_VERSION to be bumped:

• CHROME_VERSION
• CYPRESS_VERSION
• EDGE_VERSION
• FIREFOX_VERSION

This unwritten rule should be documented.

Discussion

BASE_IMAGE

Changes to BASE_IMAGE must be accompanied by a bump to FACTORY_VERSION in factory/.env. This environment variable is used in factory/docker-compose.yml and if it were not updated, then Docker images such as cypress/base, cypress/browsers and cypress/included would build on the old BASE_IMAGE value.

FACTORY_DEFAULT_NODE_VERSION

The environment variable CYPRESS_FACTORY_DEFAULT_NODE_VERSION is loaded into the cypress/factory image, so in order to release this change, and keep released images consistent with the factory/.env contents, FACTORY_VERSION must be bumped.

YARN_VERSION

The cypress/factory image does not contain Yarn. If YARN_VERSION is changed in factory/.env it does not cause any new releases of cypress/base, cypress/browsers or cypress/included to take place, since releases are only triggered when there is a change of tag. The Yarn version is not included in any tag, so there is no tag change.

Nevertheless, YARN_VERSION is a significant parameter. Bumping FACTORY_VERSION and logging the change in the factory/CHANGELOG is worthwhile simply from a documentation standpoint.

Browser versions

Browsers are not built into cypress/factory and changes should not be logged into factory/CHANGELOG or cause a change of FACTORY_VERSION.

• CHROME_VERSION
• EDGE_VERSION
• FIREFOX_VERSION

CYPRESS_VERSION

The parameter CYPRESS_VERSION in factory/.env only affects the cypress/included image, not cypress/factory, cypress/base or cypress/browsers, so changes should not be logged into factory/CHANGELOG or cause a change of FACTORY_VERSION.

Change

Add information that the FACTORY_VERSION should be changed for the following parameters, and for no others:

• BASE_IMAGE
• FACTORY_DEFAULT_NODE_VERSION
• YARN_VERSION

[MikeMcC399]

Preview

• https://github.com/MikeMcC399/cypress-docker-images/blob/factory-version-docs/CONTRIBUTING.md#new-versions
• https://github.com/MikeMcC399/cypress-docker-images/blob/factory-version-docs/factory/.env

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