【fix sonar】MailHealthIndicator文件

jero-boot/jero-boot-module-system/src/main/java/com/jero/modules/monitor/service/impl/MailHealthIndicator.java

@@ -14,6 +14,8 @@ import org.springframework.stereotype.Component;
 @Component
 public class MailHealthIndicator implements HealthIndicator {
 
+    private static final int BEST_NUMBER = 0;
+
 
     @Override public Health health() {
         int errorCode = check();
@@ -24,6 +26,6 @@ public class MailHealthIndicator implements HealthIndicator {
     }
     int check(){
         //可以实现自定义的数据库检测逻辑
-        return 0;
+        return BEST_NUMBER;
     }
 }