slf4j版本升级

xxl-job-admin/pom.xml

 		<dependency>
 			<groupId>org.slf4j</groupId>
 			<artifactId>slf4j-log4j12</artifactId>
-			<version>1.7.5</version>
+			<version>1.7.21</version>
 		</dependency>
 
 		<!-- freemarker -->

xxl-job-core/pom.xml

 		<dependency>
 			<groupId>org.slf4j</groupId>
 			<artifactId>slf4j-log4j12</artifactId>
-			<version>1.7.5</version>
+			<version>1.7.21</version>
 		</dependency>
 
 		<!-- hessian -->