Revert "[maven-release-plugin] prepare release v2.3.8"

This reverts commit 8d8c8a5152d2a3d1766fae5653fdffe990f8460c.
Revert "Update parent version for release"

This reverts commit 2c7a4af1ec1cad3de6fe0ccc2c54e5b9ba5ddae2.