"prepare" mojo calls "package", not "install"

The "prepare" mojo calls "mvn package" for the build after adapting the POM versions. This results in build failures if the project has interdependencies between modules (a rather common case). The problem is that the new version has not been deployed so far, so the required module artifacts are not yet available from the repository.

The mojo should call "mvn install" to make artifacts available to the running build process.