[maven-release-plugin] copy for tag v6.8.1 

[maven-release-plugin] copy for tag v6.8.0 

[maven-release-plugin] copy for tag v6.7.0 

[maven-release-plugin] copy for tag v6.6.0 

[maven-release-plugin] copy for tag v6.5.0 

[maven-release-plugin] copy for tag v6.4.0 

[maven-release-plugin] copy for tag v6.3.0 

[maven-release-plugin] copy for tag v6.2.0 

[maven-release-plugin] copy for tag v6.1.0 

[maven-release-plugin] copy for tag v6.0.0