@Override
	public Project build() throws IOException {
		Project project = ctx.getProject();
		createJar(project, ctx.getCompileDir(), ctx.getJarFile());
		return project;
	}
This class takes a <code>Project</code> and the result from a previous
"compile" step and packages the whole into a JAR file.
src/main/java/dev/jbang/source/buildsteps/JarBuildStep.java