Resolve the main to next sync discrepancies after the v1.6.4 release.
Conflict resolution:
- keep next package versions at 1.7.0-beta.1
- keep both changelog streams by inserting the stable 1.6.4 sections below the 1.7.0-beta entries
- restore the next pre-release accumulator changesets that the stable release deleted on main
Gustavo Valverde
225976c7d2