[maven-release-plugin] copy for tag flatpack-2.21.0

[maven-release-plugin] copy for tag flatpack-2.20.3

[maven-release-plugin] copy for tag flatpack-2.20.2

[maven-release-plugin] copy for tag flatpack-2.20.1

[maven-release-plugin] copy for tag flatpack-2.20.0

[maven-release-plugin] copy for tag flatpack-2.19.1

[maven-release-plugin] copy for tag flatpack-2.19.0

[maven-release-plugin] copy for tag flatpack-2.18.1

[maven-release-plugin] copy for tag flatpack-2.18

[maven-release-plugin] copy for tag flatpack-2.17.2