ScyllaDB release: version 1.6.4

ScyllaDB 1.6.4, a bugfix release for the ScyllaDB 1.6 stable branch, has been announced, offering backward compatibility and support for rolling upgrades. Users transitioning from version 1.5.x to 1.6.4 are advised to review the release notes due to changes in certain metrics. The update addresses several critical bugs, including issues with CQL SELECT queries from large partitions, streaming problems during Leveled Compaction Strategy repairs that could lead to out-of-memory errors, and a rare gossip bug causing node state changes to result in system exits. Users are encouraged to report any issues encountered during the upgrade process.