&& apk del .build-dependencies should be added to the base /bin/setup file.

[joshwhatk]

https://github.com/RamseyInHouse/docker-library/blob/master/node-builder/README.md#L13

We should not require people consuming this docker container to understand how it needs to clean itself up. I see no need for this line at all, however, it is still necessary. "This" is the problem.

We have a few repositories that already are missing this line, if we can get this moved into /bin/setup no one will have to care why it's there or know about it unless they need a really custom setup.