Changes to volume extension protocol

[lukemarsden]

@progrium and I talked about normalising the data structure passed back and forth so that the response is always the same structure as the request.

Conceptually it's like passing a reference to an object to multiple plugins and allowing them to mutate them.

This is currently only documented roughly here: https://github.com/lukemarsden/docker/blob/docker-extensions-proposal/docs/sources/reference/plugin-mvp.md

[lukemarsden]

The volumes extension spec has changed now, and that work is on a separate track.

[tomdee]

Are you talking about this (#14) or something else?