Change default behaviour of build update-deps to ignore milestones.

[KristianAN]

Currently when running bleep build update-deps it will update from non-milestone to milestone (possibly also RC?). In almost all cases this is not wanted behaviour. The default should be to update to the newest non-milestone/RC version. Maybe add a flag that can override this and just update to the newest whatever not-snapshot.

Already defined milestones/RC should update to latest milestone/RC

[oyvindberg]

Also note that this would be a fantastic place to start to write an interactive interface so users can cherry-pick the updates they want, control if they want to just bump all minor versions, and control which major versions to bump .