Revert "[maven-release-plugin] prepare for next development iteration"

This reverts commit 2354acb5c3b6e42c51cd6775dab9d38f5a268183.
Revert "[maven-release-plugin] prepare release maven-support-6.2.1"

This reverts commit 3b1bfce001caf0c1b22be6285c96e31778e8e7e0.