* add packagespec build system

- The majority of changes in this commit are files generated
  by packagespec (everything in the packages-oss.lock directory).

* add .yamllint

* update to packagespec@fd54aea4

* ci: bust packagespec cache

- Change to packagespec results in package IDs that can use
  git tag refs, not just commit refs.

* update to packagepsec@5fc121d0

- This busts all caches, because of a change to the way we
  no longer traverse from tag refs to commit refs, due to
  the potential confusion this can cause.
- See https://github.com/hashicorp/packagespec/commit/fd54aea4827bb6cfd637c78a2ab6274111605330
  for the original change to packagespec necessitating this.

* update to packagespec@5e6c87b6

- This completes the change to allowing git tag refs
  to be used for source IDs, begun in f130b940a8fbe3e9398225b08ea1d63420bef7b6

* update to packagespec@4d3c9e8b

- This busts cache, needed to apply previous change.

* remove RELEASE_BUIL...