servicecomb not support patchForObject

### 使用RestTemplateBuilder.create()创建出来的restTemplate无法通过patchForObject发送patch请求
请求示例
```
restTemplate.patchForObject("cse://test-provider2/provider/tomcat/patch", httpEntity, Map.class);
```
异常如下
```
2021-12-02 10:08:18.361 ERROR 1008 --- [oup0-1-thread-1] o.a.s.c.h.impl.ProducerOperationHandler : unexpected error operation=PRODUCER rest test-consumer2.helloConsumer.sayHello, message=null, cause=I/O error on PATCH request for "cse://test-provider2/provider/tomcat/patch": Null OutputStream is not a valid argument; nested exception is com.fasterxml.jackson.core.JsonGenerationException: Null OutputStream is not a valid argument
```
### 报错原因
org.apache.servicecomb.provider.springmvc.reference.CseClientHttpRequest 类的public OutputStream getBody() 这个方法return为null