[maven-release-plugin] prepare release hop-2.9.0

[maven-release-plugin] copy for tag hop-2.9.0

[maven-release-plugin] copy for tag 2.8.0-rc1

[maven-release-plugin] copy for tag 2.7.0-rc1

[maven-release-plugin] copy for tag 2.6.0-rc1

[maven-release-plugin] copy for tag 2.5.0-rc1

[maven-release-plugin] copy for tag 2.4.0-rc1

[maven-release-plugin] copy for tag 2.3.0-rc1

[maven-release-plugin] copy for tag 2.2.0-rc1

Create release version 2.1.0