Adds build steps in makefile for building Chrome and Firefox betas

[jamesmortensen]

Build steps to build Chrome Beta and Firefox Beta nodes and standalone from the makefile. Fixes #1286

Description

When running make build, all of the images will be built, including four more additional images:

• node-chrome beta
• node-firefox beta
• standalone-chrome beta
• standalone-firefox beta

Beta images can also be built using make chrome_beta and make standalone_chrome_beta and so forth.

The tag '-beta' is added to the end of the build date. For instance, selenium/node-chrome:20220815-beta

Motivation and Context

Some community members want to run tests on up and coming versions of these browsers so they can be more informed when a change in the browser code may affect their application. This first step makes it easier for users to build the images themselves and paves the way for these images to be deployed to Docker Hub via the CI pipeline.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the contributing document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

I've marked this as a draft PR as more work needs to be done to complete it.

[jamesmortensen]

I also marked this as a draft pull request since it will be easier to merge #1656 before making the full set of changes for automatically building Chrome and Firefox betas...

[jamesmortensen]

Here is a test release that shows what the release notes might look like. https://github.com/jamesmortensen/docker-selenium/releases/tag/4.4.0-20220816. I limited the beta tag to only being placed on the 4.4.0-20220816-beta "grid and build date" tag. Also, the release notes include the hash from Docker Hub as well.

Please let me know if there's any changes needed to the release notes or tags, and I'll move the necessary from the "test-beta-deploy" branch to the PR branch. (Some modifications to perform the test as "jamesmortensen1" need to be removed prior to merging this.)

[jamesmortensen]

fixes #1286

[jamesmortensen]

I just realized the docs may need to be updated. Just FYI.

[diemol]

Thank you, @jamesmortensen! This is great!

We can have a separate PR for the README to briefly document the existence of these images.