Update logback.xml

projectname-admin/src/main/resources/logback.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <configuration>
     <!-- 日志存放路径 -->
-	<property name="root" value="${log.path}" />
+	<property name="root" value="${log.path:-./logs}" />
     <!-- 日志输出格式 -->
 	<property name="log.pattern" value="%d{HH:mm:ss.SSS} [%thread] %-5level %logger{20} - [%method,%line] - %msg%n" />