spring-boot-maven-plugin 会自动生成 start-class, 但是 shade 不会

<properties>
  <start-class>com.lls.it.cpp.CppApplication</start-class>
</properties>
<plugin>
  <artifactId>maven-shade-plugin</artifactId>
  <executions>
      <execution>
          <phase>package</phase>
          <goals>
              <goal>shade</goal>
          </goals>
          <configuration>
              <transformers>
                  <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                      <resource>META-INF/spring.handlers</resource>
                  </transformer>
                  <transformer implementation="org.springframework.boot.maven.PropertiesMergingResourceTransformer">
                      <resource>META-INF/spring.factories</resource>
                  </transformer>
                  <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                      <resource>META-INF/spring.schemas</resource>
                  </transformer>
                  <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
                  <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                      <mainClass>${start-class}</mainClass>
                  </transformer>
              </transformers>
          </configuration>
      </execution>
  </executions>
  <dependencies>
      <dependency>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-maven-plugin</artifactId>
          <version>2.0.4.RELEASE</version>
      </dependency>
  </dependencies>
  <configuration>
      <keepDependenciesWithProvidedScope>true</keepDependenciesWithProvidedScope>
      <createDependencyReducedPom>true</createDependencyReducedPom>
      <filters>
          <filter>
              <artifact>*:*</artifact>
              <excludes>
                  <exclude>META-INF/*.SF</exclude>
                  <exclude>META-INF/*.DSA</exclude>
                  <exclude>META-INF/*.RSA</exclude>
              </excludes>
          </filter>
      </filters>
  </configuration>
</plugin>