Update Maven Compiler version to `3.6.2`
Update Maven Compiler version to `3.6.2`

BoykoAlex/spring-cloud-dataflow-ui,ghillert/spring-cloud-dataflow-ui,spring-cloud/spring-cloud-dataflow-ui,cppwfs/spring-cloud-dataflow-ui,cppwfs/spring-cloud-dataflow-ui,ghillert/spring-cloud-dataflow-ui,spring-cloud/spring-cloud-dataflow-ui,cppwfs/spring-cloud-dataflow-ui,BoykoAlex/spring-cloud-dataflow-ui,cppwfs/spring-cloud-dataflow-ui,BoykoAlex/spring-cloud-dataflow-ui,BoykoAlex/spring-cloud-dataflow-ui,spring-cloud/spring-cloud-dataflow-ui,spring-cloud/spring-cloud-dataflow-ui,ghillert/spring-cloud-dataflow-ui,ghillert/spring-cloud-dataflow-ui