Task generates potentially invalid versions

[matthid]

Usually whens using the task is used in a build process the build number is set in the "Build number format". However, there are situation where this field already contains a version number and cannot be changed for compatibility reasons (for example if you want to use the "version task" for a sub-component).

In the above situation:

• the version task generates "invalid" versions without yielding an error -> Bug
• there is no way to specify how to properly construct a valid version -> Needs a regex similar to the release task (new feature)

Ideally, we find a "better" way to retrieve the build number and use that instead, which should fix both issues.