upgrade bolt version to 1.6.8 (#348)

Co-authored-by: liujianjun.ljj <liujianjun.ljj@antgroup.com>

Author: EvenLjj

pom.xml

@@ -22,7 +22,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.alipay.sofa</groupId>
     <artifactId>bolt</artifactId>
-    <version>1.6.7</version>
+    <version>1.6.8</version>
     <packaging>jar</packaging>
 
     <name>${project.groupId}:${project.artifactId}</name>