as it is requested in jgitver/jgitver-maven-plugin#134, jgitver/jgitver-maven-plugin#132, jgitver/jgitver-maven-plugin#56 we should provide a mean of computing the 'next' version even when HEAD is on a version tag:

• automatically if in a dirty state : ie someone started to work for next version even without committing new stuff
• by a flag to force computation of 'next version'

This way, if we consider a repository, checkout on master branch tagged with 1.0.0
Using a maven mode without using dirty state:

• without modification: jgitver will return 1.0.0
• with some modification: jgitver will return 1.0.1-SNAPSHOT
• without modification but a force flag: jgitver will return 1.0.1-SNAPSHOT