Feature request: check that the "previous" version exists

[tonyo]

When preparing a release, validate the new release number by checking if there's a release that might be called "previous".
Example: when we're releasing version 1.2.4, 1.2.3 should probably exist.

[jan-auer]

It would be super cool to say “prepare patch” instead. Then it checks the last version and bumps up.

[BYK]

This became quite feasible after #285. We can combine this with https://github.com/npm/node-semver and achieve what @jan-auer suggested.

Would this still be cool?

[BYK]

We now have #656 so closing. @jan-auer give that a try when you have a chance.