release 2.1.0

[maven-release-plugin] copy for tag v2.0.2

[maven-release-plugin] copy for tag v2.0.1

[maven-release-plugin] copy for tag v2.0.0

[maven-release-plugin] copy for tag v1.3.0

[maven-release-plugin] copy for tag v1.2.1

[maven-release-plugin] copy for tag v1.2.0

[maven-release-plugin] copy for tag v1.1.2

[maven-release-plugin] copy for tag v1.1.1

[maven-release-plugin] copy for tag v1.1.0