README

===build fresh docker images for the CI===

• edit the docker container definitions in this folder
• make sure https://dlcdn.apache.org/maven/maven-3 still has the VER found in the java docker files
• run the infrastructure pipeline with the rebuild-images parameter set to test (test runner + driver images), build (Ubuntu compiler image), or all (both).
• the pipeline builds and pushes the images, then automatically commits the updated image tags back to the triggering branch (the default values in .circleci/config.yml, .circleci/base_config.yml, and — for the build image — .circleci/nightly_packages.yml and .circleci/base_nightly_packages.yml). No manual tag editing is needed.
• images already built for the current commit are skipped, so re-running the pipeline on the same commit is a no-op.

push the PR, merge it - done.