This makes sure that the latest version of the core SDK components are
all current before running, which means that the builds will keep
working even when the docker image gets out of date. Then we can
finish the task we are working on before having to deal with updating
the docker image. Without that update line, we have to drop everything
and update the docker image when things are out of date.

Disk space and bandwidth is cheap, developer time is very scarce. We
should aim to keep the tests working as much as possible so that we
waste less developer time. Updating everytime only means it downloads
a little bit of XML each time, that's nothing compared to what gradle
downloads on every build.