update nacos version in 2021.x (#3069)

* update nacos client to 2.2.0

spring-cloud-alibaba-dependencies/pom.xml

@@ -21,7 +21,7 @@
         <revision>2021.0.4.0-SNAPSHOT</revision>
         <sentinel.version>1.8.5</sentinel.version>
         <seata.version>1.5.2</seata.version>
-        <nacos.client.version>2.0.4</nacos.client.version>
+        <nacos.client.version>2.2.0</nacos.client.version>
         <spring.context.support.version>1.0.11</spring.context.support.version>
 
         <!-- Maven Plugin Versions -->

spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-nacos-discovery/src/test/java/com/alibaba/cloud/nacos/registry/MockNamingService.java

@@ -74,6 +74,18 @@ public class MockNamingService implements NamingService {
 
 	}
 
+	@Override
+	public void batchRegisterInstance(String serviceName, String groupName, List<Instance> instances)
+			throws NacosException {
+
+	}
+
+	@Override
+	public void batchDeregisterInstance(String serviceName, String groupName, List<Instance> instances)
+			throws NacosException {
+
+	}
+
 	@Override
 	public void deregisterInstance(String serviceName, String groupName, String ip,
 			int port) throws NacosException {