increased java version to 1.8 and removed `maven-compiler-plugin` plugin in favor of <maven.compiler.*> properties
increased java version to 1.8 and removed `maven-compiler-plugin` plugin in favor of <maven.compiler.*> properties

Signed-off-by: Victor Ursan <3afdf24b104189ac4177a1346078f9d352c70c06@hpe.com>

CloudSlang/score,CloudSlang/score