fix：iot-gateway-server 的 spring-boot-maven-plugin 缺少版本号，对应 https://gitee.com/zhijiantianya/yudao-cloud/issues/ID5LU4

yudao-module-iot/yudao-module-iot-gateway/pom.xml

@@ -64,6 +64,7 @@
             <plugin>
                 <groupId>org.springframework.boot</groupId>
                 <artifactId>spring-boot-maven-plugin</artifactId>
+                <version>${spring.boot.version}</version>
                 <executions>
                     <execution>
                         <goals>