update default dependency.
spring framework: 4.3.16.RELEASE -> 5.1.6.RELEASE
spring boot: 1.5.12.REALESE -> 2.1.4.RELEASE
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
+ <spring.framework.version>5.1.6.RELEASE</spring.framework.version>
+ <spring.boot.version>2.1.4.RELEASE</spring.boot.version>
+
<!--
<spring.framework.version>5.1.1.RELEASE</spring.framework.version>
<spring.boot.version>2.0.5.RELEASE</spring.boot.version>
<spring.boot.version>2.0.0.RELEASE</spring.boot.version>
-->
+ <!--
<spring.framework.version>4.3.16.RELEASE</spring.framework.version>
<spring.boot.version>1.5.12.RELEASE</spring.boot.version>
+ -->
<!--
<spring.framework.version>4.3.5.RELEASE</spring.framework.version>
