fix: 增加 3.1.6 标签

Author: mazhanghui

README.md

@@ -11,12 +11,12 @@ RongCloud IM Server SDK in Java.
     <dependency>
         <groupId>cn.rongcloud.im</groupId>
         <artifactId>server-sdk-java</artifactId>
-        <version>3.1.5</version>
+        <version>3.1.6</version>
     </dependency>
 ```
    * Gradle
 ```
-    compile group: 'cn.rongcloud.im', name: 'server-sdk-java', version: '3.1.5'
+    compile group: 'cn.rongcloud.im', name: 'server-sdk-java', version: '3.1.6'
    
 ```
    * 基于源码 Meavn 打包构建

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>cn.rongcloud.im</groupId>
     <artifactId>server-sdk-java</artifactId>
-    <version>3.1.5</version>
+    <version>3.1.6</version>
     <packaging>jar</packaging>
 
     <name>RongCloud IM Server SDK</name>