Confirmation prompt for tar_destroy()

[gofford]

targets is an excellent framework, and has reduced code-complexity in my projects immeasurably.

However, the tar_destroy() functions feels very heavy handed at the moment. It is single-use, and non-recoverable. If I (or a collaborator) accidentally types it our entire artefact history is gone.

Have you considered adding a confirmation prompt to this function? I.e., tar_destroy() -> "Are you sure?" -> Yes.

[wlandau]

A prompt is a good idea, added in e46f178. And there are several cleaning functions that are less extreme than tar_destroy(): https://docs.ropensci.org/targets/reference/index.html#section-clean