[Discussion]about spring-boot2 dependencies

[bismy]

In PR[1] add a new dependency management for spring boot2, that is 
java-chassis-dependencies-springboot2/pom.xml


This file is a bit huge and I think we can simplify by adding 


<dependencyManagement>
                <dependencies>
                <dependency>
                        <!-- Import dependency management from Spring Boot -->
                        <groupId>org.springframework.boot</groupId>
                        <artifactId>spring-boot-dependencies</artifactId>
                        <version>2.0.5.RELEASE</version>
                        <type>pom</type>
                        <scope>import</scope>
                </dependency>
        </dependencies>
</dependencyManagement>



Do we have any special reasons that do not use this feature provided by spring 
boot?


[1]https://github.com/apache/incubator-servicecomb-java-chassis/pull/906/files