Provide information about the next version number

[calmh]

I often have a need to know the upcoming version number during build, before the release. It would be very helpful if semantic-release could provide this information when run in non-release mode: "if we released now, this would be the version number". Things I use this for:

• When releasing mobile apps they need to go into app review and whatnot. This means we need to push a binary that is (internally) tagged 1.2.3 and behaves as 1.2.3, before we actually release version 1.2.3. (We might get pushback in the review and have to make another build, so we ideally don't want to actually tag and release 1.2.3 before it's passed.
• Similar for other binaries, once we released 1.2.2 the next build should internally be known as something like 1.2.3-dev.1, etc. Having the build action tell us "1.2.3" and then, if we push a feature, "1.3.0" etc would be helpful here.