We added support for building and testing against a Docker image based on the latest Kafka trunk in #376. The image is automatically built the first time tests are run with CONNECT_VERSION=TRUNK, and cached for subsequent runs.

This is great for cutting down test runtime, but may lead to using a stale image the next day, month, etc. We may want to add a cleaner way to force a rebuild of the image aside from manually deleting the debezium/connect:trunk image.

Some options @mfvitale provided on that PR include:

• Put the deletion of the image by default and then add a property to force the reuse of the image (so the dev is conscious of what is doing).
• Leave the image deletion active by default and then delete it on Maven clean using docker-maven-plugin