Eliminate warning on duplicate classes

[melahn]

When building the shaded jar, observe this warning:

SparseBitSet-1.2.jar, commons-cli-1.4.jar, commons-codec-1.13.jar, commons-collections4-4.4.jar, commons-compress-1.19.jar, commons-math3-3.6.1.jar, curvesapi-1.06.jar, hamcrest-core-1.3.jar, junit-4.13.jar, poi-4.1.2.jar, poi-ooxml-4.1.2.jar, poi-ooxml-schemas-4.1.2.jar, user-story-generator-1.0.0.jar, xmlbeans-3.1.0.jar define 1 overlapping resources:

• META-INF/MANIFEST.MF
  commons-cli-1.4.jar, commons-codec-1.13.jar, commons-collections4-4.4.jar, commons-compress-1.19.jar, commons-math3-3.6.1.jar define 2 overlapping resources:
• META-INF/LICENSE.txt
• META-INF/NOTICE.txt
  hamcrest-core-1.3.jar, xmlbeans-3.1.0.jar define 1 overlapping resources:
• LICENSE.txt
  poi-4.1.2.jar, poi-ooxml-4.1.2.jar, poi-ooxml-schemas-4.1.2.jar define 2 overlapping resources:
• META-INF/LICENSE
• META-INF/NOTICE
  maven-shade-plugin has detected that some class files are
  present in two or more JARs. When this happens, only one
  single version of the class is copied to the uber jar.
  Usually this is not harmful and you can skip these warnings,
  otherwise try to manually exclude artifacts based on
  mvn dependency:tree -Ddetail=true and the above output.
  See http://maven.apache.org/plugins/maven-shade-plugin/

Try to eliminate it.