更新channel接口，订阅/取消订阅只能逐个操作

common/src/main/java/cn/wildfirechat/common/APIPath.java

@@ -52,7 +52,6 @@ public interface APIPath {
     String Channel_Update_Profile = "/channel/update_profile";
     String Channel_Message_Send = "/channel/message/send";
     String Channel_Subscribe = "/channel/subscribe";
-    String Channel_Unsubscribe = "/channel/unsubscribe";
     String Channel_Subscriber_List = "/channel/subscriber_list";
 
     String Robot_User_Info = "/robot/user_info";

common/src/main/java/cn/wildfirechat/pojos/InputChannelSubscribe.java

@@ -15,15 +15,15 @@ import java.util.ArrayList;
 import java.util.List;
 
 public class InputChannelSubscribe {
-    private List<String> targets;
+    private String target;
     private int subscribe; //1，订阅；0，取消订阅
 
-    public List<String> getTargets() {
-        return targets;
+    public String getTarget() {
+        return target;
     }
 
-    public void setTargets(List<String> targets) {
-        this.targets = targets;
+    public void setTarget(String target) {
+        this.target = target;
     }
 
     public int getSubscribe() {