Change build target to package

Avoids the verify maven goal which skips the OWASP checks.
OWASP is not featured in this example.

basic-spring-boot/Jenkinsfile

@@ -45,7 +45,7 @@ pipeline {
     // Run Maven build, skipping tests
     stage('Build'){
       steps {
-        sh "mvn -B clean install -DskipTests=true -f ${POM_FILE}"
+        sh "mvn -B clean package -DskipTests=true -f ${POM_FILE}"
       }
     }