Allow for caching tasks that fail, while still preserving their non-zero exit code

[john-privy]

Goals

1. Allow re-running tasks that fail and getting cached output when their dependencies have not changed. For example, I should be able to turbo test twice and get cached output the second time when some tests fail.

Non-goals

No response

Background

The best alternative I know of is to add || exit 0 to npm scripts that are being run, but it's useful to have the actual code (e.g. in CI) still propagated, so I don't think this is a good workaround.

I couldn't find anything else on the subject.

Proposal

Add a global and/or task level configuration option to support caching tasks that fail.