Add a flag that changes the exit code of `version` to 0 even if there are no new files

[wkillerud]

At the time of writing the eik version command does a comparison of the files currently up on Eik and the ones that are on the local or CI machine, that are about to be (maybe) published.

• eik version exits with an error code if there are no new or changed files locally. https://github.com/eik-lib/cli/blob/37a6139f70f1ff05f71af7d381261d4658e643bc/classes/version.js#L158-L162
• eik publish, however, exits with code 0 if the user tries to publish to a version that already exists. https://github.com/eik-lib/cli/blob/37a6139f70f1ff05f71af7d381261d4658e643bc/utils/error.js#L27-L29

The exit code for eik version makes it a bit tricky to write automated release workflows using the CLI. In a lot of our projects we do want to continue the CI workflow to deploy the server-side of things, even if the client-side hasn't changed.

I see the use for some kind of signal that "hey, nothing changed, you don't have to continue", so I don't want to change the default behaviour of eik version.

However, some kind of flag that changes the exit code to 0 would be useful. There are workarounds of course, but some kind of designed solution would be nice.

[wkillerud]

Relates to https://github.com/eik-lib/eik-lib.github.io/issues/108

[wkillerud]

A commonly used workaround that achieves the same result, since eik publish exits 0:

eik version || true && eik publish

Documented in the context of GitHub Actions here, including committing eik.json if there are changes: https://github.com/eik-lib/eik-lib.github.io/pull/115