The docker-comjpose file raises the question is there some handy way for versioning the used docker images in the docker-compose.yml, like pip / npm have? You would usually want to control for browser versions in this kind of testing, no?
While Docker definitely supports tagging versions, I've decided to not tag the example images for now.
The main reason for this is that it would be very difficult to properly express what a version stands for.
e.g. there are multiple changing parts in the chromedriver image:
1. The Chrome version
2. The Chromedriver version (although this tied to the Chrome version)
3. The Docker image configuration
I will try to keep changes to the chromedriver/geckodriver image configurations to a minimum, but also won't guarantee so.
Another reason not to tag those images is that Chrome/Firefox use a rolling release system, making Chrome/Firefox versions less meaningful, as usually the latest version is the most important to test.
My recommendation for anyone using the those images for production CI infrastructure is to create a fork of the repos and your own Docker automated builds.
