#436 添加一次性订阅消息接口

weixin-java-open/src/main/java/me/chanjar/weixin/open/api/impl/WxOpenInMemoryConfigStorage.java

@@ -342,6 +342,11 @@ public class WxOpenInMemoryConfigStorage implements WxOpenConfigStorage {
       return wxOpenConfigStorage.getComponentToken();
     }
 
+    @Override
+    public String getTemplateId() {
+      return null;
+    }
+
     @Override
     public long getExpiresTime() {
       return 0;