flatten plugin cannot be loaded due to jgitver

### Before submitting an issue I have first:

- [x] searched for similar already existing issue
- [x] read the documentation and [wiki](https://github.com/jgitver/jgitver-maven-plugin/wiki)

## Issue

flatten plugin cannot be loaded because jgitver has no bound implementation

1.7.0:

- [x] maven command line: 3.5.0, 3.6.3

Parent POM has flatten-plugin 1.2.5 (I try to use the latest version to get around the classifier issue https://github.com/mojohaus/flatten-maven-plugin/issues/132) configured as follows

```

org.codehaus.mojo
flatten-maven-plugin
1.2.5

${project.build.directory}
pom.xml



flatten-poms
package

flatten



flatten-clean
clean

clean




```

The following happens when children POM is flattened

```
[ERROR] Failed to execute goal org.codehaus.mojo:flatten-maven-plugin:1.2.5:flatten (flatten-poms) on project giad-war: Execution flatten-poms of goal org.codehaus.mojo:flatten-maven-plugin:1.2.5:flatten failed: Unable to load the mojo 'flatten' (or one of its required components) from the plugin 'org.codehaus.mojo:flatten-maven-plugin:1.2.5': com.google.inject.ProvisionException: Unable to provision, see the following errors:
[ERROR]
[ERROR] 1) No implementation for fr.brouillard.oss.jgitver.JGitverConfiguration was bound.
[ERROR] while locating fr.brouillard.oss.jgitver.JGitverModelProcessor
[ERROR] at ClassRealm[plugin>fr.brouillard.oss:jgitver-maven-plugin:1.7.0, parent: sun.misc.Launcher$AppClassLoader@7852e922] (via modules: org.eclipse.sisu.wire.WireModule -> org.eclipse.sisu.plexus.PlexusBindingModule)
[ERROR] at ClassRealm[plugin>fr.brouillard.oss:jgitver-maven-plugin:1.7.0, parent: sun.misc.Launcher$AppClassLoader@7852e922] (via modules: org.eclipse.sisu.wire.WireModule -> org.eclipse.sisu.plexus.PlexusBindingModule)
[ERROR] while locating org.apache.maven.model.building.ModelProcessor
[ERROR] at org.eclipse.sisu.wire.LocatorWiring
[ERROR] while locating org.apache.maven.model.building.ModelProcessor
[ERROR] for field at org.codehaus.mojo.flatten.ModelBuilderThreadSafetyWorkaround.modelProcessor(Unknown Source)
[ERROR] while locating org.codehaus.mojo.flatten.ModelBuilderThreadSafetyWorkaround
[ERROR] for field at org.codehaus.mojo.flatten.FlattenMojo.modelBuilderThreadSafetyWorkaround(Unknown Source)
[ERROR] while locating org.codehaus.mojo.flatten.FlattenMojo
[ERROR] at ClassRealm[plugin>org.codehaus.mojo:flatten-maven-plugin:1.2.5, parent: sun.misc.Launcher$AppClassLoader@7852e922] (via modules: org.eclipse.sisu.wire.WireModule -> org.eclipse.sisu.plexus.PlexusBindingModule)
[ERROR] while locating org.apache.maven.plugin.Mojo annotated with @com.google.inject.name.Named(value=org.codehaus.mojo:flatten-maven-plugin:1.2.5:flatten)
[ERROR]
[ERROR] 1 error
[ERROR] role: org.apache.maven.plugin.Mojo
[ERROR] roleHint: org.codehaus.mojo:flatten-maven-plugin:1.2.5:flatten

```