更新RM；

README.md

 <dependency>
     <groupId>com.xuxueli</groupId>
     <artifactId>xxl-job-core</artifactId>
-    <version>1.7.0</version>
+    <version>1.7.1</version>
 </dependency>
 ```
 

xxl-job-executor-example/pom.xml

 		<dependency>
 			<groupId>org.slf4j</groupId>
 			<artifactId>slf4j-log4j12</artifactId>
-			<version>1.7.5</version>
+			<version>1.7.21</version>
 		</dependency>
 		
 		<!-- c3p0 -->