"-g" prefix option not available in maven plugin

### Before submitting an issue I have first:

- [x] searched for similar already existing issue

Found [completed](https://github.com/jgitver/jgitver/commit/498cf53a100116142e30cbb331a7d8c16d398eee) issue in the underlying library https://github.com/jgitver/jgitver/issues/24.

The functionality does not seem to be exposed in `jgitver-maven-plugin`.

## Issue

**version**: 1.5.1

**usage context**:

- [x] maven command line: 3.6.0

**Problem description**:

- with `useGitCommitId` set to `true` the generated name does not contain '-g' before the hash
e.g. in repository one commit after `v0.0.1` tag:
- jgitver-maven-plugin produces `...-0.0.1-1-d1590b8f`
- sbt-git produces `...-0.0.1-1-gd1590b8`

**Attempts**:
- using `true` in xml configuration fails with:
```
Element 'useLongFormat' does not have a match in class fr.brouillard.oss.jgitver.cfg.Configuration
```
- [xsd](https://jgitver.github.io/maven/configuration/jgitver-configuration-v1_1_0.xsd) does not contain "useLongFormat" or anything similar.
- GitHub search for `setUseLongFormat` returns no results in `jgitver-maven-plugin`.