Bump up Java agent core to 8.13.0

Author: wu-sheng

README.md

@@ -7,9 +7,7 @@ Including
 1. Oracle JDBC Driver
 1. Aliyun ONS 1.x
 
-To be clear, these plugins have no license issue, but need Apache 2.0 uncompatible license Jar file to compile, which is not allowed to do in Apache. 
-
-2.0+ releases require SkyWalking 8.2.0+
+To be clear, these plugins have no license issue, but need Apache 2.0 uncompatible license Jar file to compile, which is not allowed to do in Apache.
 
 # License
 Apache 2.0

pom.xml

@@ -19,7 +19,7 @@
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <skywalking.version>8.8.0</skywalking.version>
+        <skywalking.version>8.13.0</skywalking.version>
         <shade.package>org.apache.skywalking.apm.dependencies</shade.package>
         <shade.net.bytebuddy.source>net.bytebuddy</shade.net.bytebuddy.source>
         <shade.net.bytebuddy.target>${shade.package}.${shade.net.bytebuddy.source}</shade.net.bytebuddy.target>